For the next few days Penny saw very little of her father. He left the house early in the morning and often did not return at night until after she had retired. Meals became something of an ordeal, for either Mr. Nichols buried himself in a newspaper or allowed the conversation to lapse.
"You're as talkative as the sphinx!" Penny accused. "Is the case going badly?"
"Not to my knowledge."
"Is it going well then?"
"Not especially."
"Have you found any clue as to the whereabouts of Rap Molberg?"
"Not yet."
"You're impossible!" Penny cried furiously. "It's no use trying to learn a thing from you unless you're in exactly the right mood!"
In desperation she sought solace in the companionship of her chum, Susan. They attended a great many moving picture shows and developed an enviable tan by swimming outdoors and playing tennis for hours at a time.
Although Penny was permitted complete freedom, Mr. Nichols had warned her to use caution whenever she left the house at night. On more than one occasion in going downtown or to the home of a friend, she half suspected that she was being followed.
She refrained from mentioning her fear to Mr. Nichols lest he curtail her freedom. But she became more alert and watchful.
One afternoon while Penny was mowing the yard, Susan drove up in her coupé. It was the first time she had used it since the unfortunate night of the theft. She hailed Penny joyously.
"The old bus is traveling again! It has a new generator and a fine new wheel!"
Penny inspected the new purchases.
"See anything wrong with the wheel?" Susan demanded.
"Not a thing. Why?"
"I bought it for about half the regular price. I was a little afraid I might have been gipped."
Penny examined the spare wheel more critically. "It looks exactly like the one Dad bought me some time ago for nine ninety-eight. In fact, I'd think it was the same tire—the one that was stolen from me—if I didn't know better."
"I only paid four dollars," Susan informed proudly. "Wasn't it a bargain?"
"It looks like it. Where did you buy the tire?"
"Oh, at a little place on South Lake Street. I don't remember the name."
"South Lake isn't such a good location," Penny said thoughtfully, "I've heard Father say that a great many disreputable firms operate there. I know once he traced stolen furniture to a dealer on that street."
"I hope I didn't buy a stolen wheel," Susan declared. "Was that what you had in mind, Penny?"
"I thought of it right off. But I haven't any reason for saying it. For all I know, your tire may be a legitimate bargain."
"I wish there was some way of finding out for certain," Susan said anxiously.
"Let's look for the serial number. The wheel should have one."
Penny moved closer to inspect the new purchase.
"The number is here all right," she acknowledged.
"Then the tire wasn't stolen," Susan said in relief.
Penny shook her head. "I'm not so sure of that, Sue. It looks to me as if these numbers have been changed. Wait a minute!"
She darted into the house, returning with her father's magnifying glass. Using it to study the figures upon the wheel, the girls could plainly see that the numbers had been altered.
"To think I'd buy a stolen wheel!" Susan exclaimed indignantly. "I'm going right back and tell that dealer a thing or two!"
"You can't very well do that. We would be in no position to prove anything."
"I suppose you're right," Susan admitted.
"I'd like to see the establishment where you bought the tire," Penny said after a moment's pause. "Could you point it out to me?"
"Yes, I'll take you there now if you like."
Penny rolled the lawn mower into the garage and climbed into the coupé beside her chum.
"How do you like your car by this time?" she inquired as they drove toward South Lake Street.
"Not so well. It starts hard and has a funny sound in the engine. In a few days I mean to take it back to the Brunner garage for a complete overhaul."
South Lake Street was located in the poorer section of Belton City. The neighborhood was noted for its second-hand stores and it was said that sooner or later stolen merchandise found its way into the crowded little shops which lined the narrow thoroughfare. Often wares were piled upon the sidewalks to attract an unwary buyer. Stoves, cheap tables, and all manner of hardware rubbed elbows with clever brass jugs, imported vases and Oriental rugs.
Presently, Susan halted her car in front of a tire shop which was located at the outskirts of "second hand" row.
"This is the place," she announced.
The owner of the shop, a short, squat little man with beady black eyes, stood at the window. He eyed the girls sharply.
"Shall we go in?" Susan asked.
"Let's, but we mustn't act as if we suspect anything."
Assuming a casual attitude, they sauntered into the shop. The dealer recognized Susan instantly. On her first visit he had been a trifle too cordial, but now he regarded her shrewdly.
"Something?" he inquired.
"My friend wishes to buy a new wheel," Susan informed. "She'd like to see one like I bought yesterday."
Again the dealer cast a sharp glance at Penny.
"Haven't I seen you in here before?" he asked.
Penny shook her head. "No, this is the first time I ever came into your store."
"I've seen you somewhere," the man muttered. "Now, I know! You're Christopher Nichols' daughter!" He pronounced the name of the detective with a slight sneer.
"Yes, I am," Penny acknowledged reluctantly. "But I'm sure I've never seen you before."
"That's quite likely."
"Then how did you know me?"
"That's my business," the dealer retorted shortly. "I am sorry, but I can't do business with you. Good day."
Penny stood her ground.
"Haven't you any tires for sale?"
"Not for you, I haven't. You're a snooper just like your father! Get out of here!"
Penny would have carried the argument further, but Susan tugged at her sleeve. They hastily left the shop. As they drove away, they saw the dealer standing at the plate glass window, watching.
"Such a horrible man!" Susan gasped. "I was actually afraid of him. What made him act like that?"
"I think he must have guessed why we came," Penny told her. "As a sleuth I seem to be a walking advertisement of my calling!"
"He recognized you the minute you stepped into the store. Didn't that strike you as queer?"
"Yes, it did, Susan. I'm almost certain that man is dealing in stolen tires. He's probably afraid of the law. It's to his advantage to recognize plain clothesmen and persons who might cause him trouble, I imagine I've been seen with my father."
"I should think the police could arrest him."
"It isn't as easy as one might believe, Susan. If a fence is caught with stolen merchandise he claims to have purchased it in good faith. Actually he has taken it off the hands of some thief. An arrest is hard to make."
"Then there's nothing we can do?"
"I don't know. I'll ask Father when he comes home tonight."
"I think a fence is even more contemptible than a thief," Susan said scornfully. "I'd give anything if I hadn't bought that tire."
"I'm glad you did," Penny smiled, "for the clue we gained may prove useful to Father."
The girls were relieved when they reached the end of South Lake and turned into a more pleasant street. Driving toward their homes they relapsed into a long silence, each absorbed in her own thoughts. There were occasions when the two friends talked frantically for hours. There were other times when they would speak scarcely a word, yet enjoy perfect understanding.
Penny had slumped in her seat. Suddenly, she straightened, her eyes riveted upon a pedestrian who was crossing the street in front of the coupé.
"Susan, isn't that Jerry Barrows?" she demanded excitedly.
The car swerved wildly as Susan turned to look.
"It is!" she exclaimed.
"Stop the car," Penny pleaded. "I want to talk with him."
Susan brought the coupé to a halt at the curbing. Penny sprang out.
"Jerry Barrows!" she called.
The boy wheeled and saw her. He hesitated an instant, then turned and ran.
"Wait! I want to talk with you!" Penny called.
The boy paid no heed. As she ran after him he darted into the nearest alley.
Provoked, Penny hastened back to the car where Susan was waiting.
"Let's try to catch him," she proposed, springing in beside her chum.
Susan turned the coupé in the narrow street and drove into the alley. They could see the boy only a short distance ahead.
"We'll overtake him," Penny cried jubilantly.
Aware that he was being pursued, the boy ran faster. Then noticing an opening between two buildings, he squeezed through it and was lost to view.
Penny tried to follow afoot but soon gave it up. She returned to the coupé disheartened.
"He eluded us this time, Sue. I suppose that boy thought I meant to have him arrested. Actually, I only wanted to question him."
For some twenty-five minutes the girls cruised around the block, hoping to sight Jerry Barrows again. Although they kept close watch of the alleys he did not reappear.
"Did you notice anything peculiar about that boy's appearance?" Penny inquired as they turned toward home.
"No, why?"
"He was dressed much better than on that night when we caught him in our garage. He doesn't look as if he had ever had much hard luck."
"I imagine his entire story was a lie," Susan declared. "He didn't keep his promise to call at your father's office, and now he runs like a coward when we try to talk with him."
"I don't see how I was taken in so easily," Penny confessed ruefully. "I couldn't help liking the boy. I hoped he would turn over a new leaf."
Alighting at the Nichols home, she invited her chum to remain for dinner.
"I can't tonight," Susan told her regretfully. "We're having guests."
"I suppose I'll have to eat alone then. No use expecting Dad home."
In this she was mistaken. Entering the house, she discovered Mr. Nichols submerged in his favorite easy chair.
"I didn't look for you home so early, Dad."
"Nor did I expect to make it when I left the house this morning. However, I must return to the office immediately after dinner."
"Is it so very important?" Penny demanded.
Her father smiled.
"Lonesome?"
"Not exactly, only the evenings seem so long."
"Why don't you go to a moving picture show?"
"I've seen every good one in town. Besides, I'm tired of movies."
"I realize I am being a very poor father," Mr. Nichols acknowledged, reaching over to squeeze her hand. "You might come back to the office with me."
"I'd like that," Penny said instantly.
"It will be very dull," her father warned.
Directly after dinner, they motored to Mr. Nichols new office opposite the Brunner garage. Since the detective expected to occupy it only a few weeks at the most, it was equipped with the barest of necessities. There was a battered desk, three chairs and two telephones. Nothing more.
"What in the world do you do here?" Penny questioned.
"Mostly sit and wait," the detective admitted. "I receive reports from some of my men here. During the day I watch the street."
With a wave of his hand he indicated a powerful field glass which lay upon the desk.
Penny picked it up, training it upon the Brunner garage on the opposite side of the street.
"Why, it brings everything remarkably close! Do you sit here at the window and watch for the auto thieves?"
"Something like that. We've set a trap."
"A trap?" Penny was all interest.
"Yes, we've planted several expensive new cars in key positions on the street. Our men are secretly watching them, of course. We hope that the auto thieves will select one of our models to strip."
"It must be tedious waiting."
"It is, but if we catch the gang our patience will have been rewarded."
"But what of Rap Molberg?" Penny questioned doubtfully. "Surely he must delegate the actual thievery to others."
"I'm not so sure," Mr. Nichols said slowly. "It wouldn't surprise me to learn that Molberg acts upon orders from someone higher up. However that may be, if we capture some of the lesser fry, they can be made to talk."
The detective busied himself at his desk. For a time Penny amused herself by watching pedestrians through the field glass. Growing tired of that, she buried herself in a magazine. It was not very interesting. By nine o'clock she was thoroughly bored.
"I think I'll go home," she announced. "I don't believe anything exciting will happen tonight."
"So that's why you came," her father chided. "And I thought it was because you craved my company!"
"I did, but this bare office is too depressing."
"Then I'll excuse you," Mr. Nichols smiled. "Take a taxi home if you like."
"No, I think I'll walk."
It was a pleasant mellow evening and Penny was in the mood for a long stroll. She chose a roundabout route home.
She was absent-mindedly crossing a street, thinking of nothing in particular, when an automobile without headlights shot past her at a high rate of speed. Frightened, Penny sprang backwards.
"The nerve of that driver!" she thought. "He missed me by inches."
She watched the car swerve around a corner and race up a dead-end street.
"Why, this is the very place where I lost track of Rap Molberg!" she told herself.
She rushed to the corner. Her fascinated gaze followed the retreating automobile. It tore madly to the end of the street where it abruptly halted.
Penny lost sight of it for an instant. Then to her surprise, the headlights were flashed on. In the reflected light she saw the tall walls of a large manufacturing plant.
The beam was turned off again. Darkness swallowed up the car.
While she was straining to see, Penny heard the shrill blast of a warning siren from far up the street. The next instant, a police radio cruiser shot past.
With a loud screaming of brakes, the police car came to a stop not far from Penny.
"Did you see an automobile without headlights come this way?" the driver asked tersely.
Penny was only too glad to offer information.
"It turned into this dead-end," she began.
The officers did not wait to hear more. With a roar, the cruiser was off again. It reached the end of the street and halted because it could go no farther.
Penny, bent upon missing nothing, followed as fast as she could.
By the time she reached the radio cruiser one of the officers had alighted. He was looking carefully about. Sighting Penny, he walked over to her.
"Say you! I thought you told us that car came this way."
"It did," Penny maintained staunchly. "I saw it go to the very end of this street. The lights flashed on for an instant. Then the car seemed to vanish. I think it must have gone into that building."
She indicated the Hamilton Manufacturing Plant. The officer surveyed it briefly.
"Don't kid me!" he snapped. "Only a Houdini ever went through solid walls!"
He climbed back into the police car, saying gruffly to the driver: "Get going, Philips. It was a wrong steer. We must have missed that car at the turn."
Penny waited until the cruiser disappeared around the corner. Then she crossed the street and stood staring meditatively at the tall walls of the Hamilton Plant. There was no doorway leading into the building.
"It's uncanny," she murmured. "Yet I know very well that car went in there some way." The building was entirely dark. There were no windows on the street side. Only a vast expanse of unbroken wall.
"It's too dark to see anything tonight," Penny decided after a brief hesitation. "Tomorrow I'll come back and perhaps make a few interesting discoveries!"
And with that resolution, she turned and walked rapidly toward home.
Penny fully intended to tell her father of her experience, but she retired before he came home. She overslept the next morning. When she descended to the breakfast room at nine o'clock, Mrs. Gallup told her that the detective had been gone for nearly an hour.
"Your father wasn't in a very good mood this morning," the housekeeper informed as she served Penny with a steaming hot waffle. "He complained about the coffee. When he does that it's always because something's gone wrong with his work."
"You mustn't mind Dad," Penny smiled. "We couldn't get along without you."
Mrs. Gallup sniffed.
"I do the best I can. The coffee does taste all right, doesn't it?"
"It's perfect."
"When your father's working on a hard case he always likes it strong as lye," the housekeeper complained. "But I know he was worried about something this morning."
"What makes you think so?"
"I heard him muttering to himself. Something about the stupidity of the police. It seems they let some crook get away last night after your father had laid careful plans to catch him."
"Not Rap Molberg?"
"I think that was the name. Mr. Nichols didn't tell me anything, I just heard him talking it over with himself."
"It's the only person he will discuss his business with," Penny chuckled.
After Mrs. Gallup had gone back into the kitchen she mulled over the information which the housekeeper had given her. It struck her as probable that the car which she had seen vanish down the dead-end street had been driven by Rap Molberg or one of his confederates.
"I wish I could have talked with Dad about it before he left the house," she thought.
Penny had not forgotten her resolution to visit the Hamilton Plant by daylight. As soon as she had helped Mrs. Gallup with the dishes, she left the house, walking directly to the scene of the previous evening's adventure.
The street was deserted. No one questioned her actions as she made a careful inspection of the old building which had housed the Hamilton Manufacturing Company until its failure. She examined the walls inch by inch, but although she was convinced it was there, she could find no hidden entrance.
Regardless of her failure to find evidence, Penny was unwilling to give up her original theory. She remained unshaken in her belief that the mysterious automobile had disappeared into the Hamilton building.
"There's no other place it could have gone," she reasoned. "I'll talk it over with Dad and see what he thinks."
When she stopped at his office, Mr. Nichols was not there nor could Miss Arrow tell her when he might return.
The detective did not come home for luncheon and late in the afternoon telephoned to say that he would take dinner downtown. Rather than spend an evening alone Penny called Susan, arranging that they should go to the library together.
The girls spent an hour in the reading room, but for some reason Penny could not interest herself in the magazines. She kept turning through them and laying them aside. She felt unusually restless.
Presently an electrical magazine attracted her attention. She glanced over it carelessly until she came to a particular article which dealt with photo-electric cells and the clever purposes for which they were used.
"Why, these 'magic-eyes' are almost human," she commented in an undertone to Susan. "They turn lights on and off, cook meals, and open doors, when a beam of light strikes the cell——"
"I've heard of them before," Susan interrupted in a tone which clearly implied that she was not in the least interested.
Penny took the hint and dropped the subject. But she became absorbed in the article. When she closed the magazine a half hour later, her face was flushed with excitement.
"Susan, let's get away from here," she proposed in a whisper. "I've just had an inspiration!"
Grumbling a little at being forced to leave a fascinating story before she had finished it, Susan followed her friend from the building.
"What about this inspiration of yours?" she demanded as they walked to Penny's parked roadster.
"It's this way, Susan. I knew there was a logical explanation for the mysterious disappearance of that car Rap Molberg was driving. Let's go over to the Hamilton Factory this minute and test out my new theory."
"You may know what you're talking about, but I'm sure I don't, Penny Nichols."
"That's because you wouldn't let me tell you about that article I was reading," Penny laughed. "But I'll explain everything as we go along."
Without pausing to consider that it might not be safe to investigate the abandoned manufacturing plant at such a late hour, the girls drove directly into the hilly section of Belton City. Penny turned into the familiar dead-end street and was relieved to find no sign of other vehicles.
She halted her roadster at the very end of the pavement in such a position that the bright headlights played upon the massive walls of the Hamilton building.
"It must be located higher up," Penny murmured to herself.
"What is?" Susan demanded. "I don't see what you're about anyway."
Without answering, Penny directed the beam of her spotlight upon the stone structure. Inch by inch she moved it systematically over the high wall.
"Perhaps it's only a silly idea," she acknowledged at last, "but I believe that somewhere in the wall there must be a secret door—one mechanically operated. No doubt the outline of the opening is disguised by the many irregular cracks in the masonry."
"If you're looking for a secret opening, why not come in the daytime when you can see much better?"
"I've been here in the daytime and the door can't be detected—at least not by the eye. I'm hoping to have better luck this time."
"I can't for the life of me see how," Susan began, but ended with a startled gasp.
A portion of the massive wall was slowly moving backward.
"Just as I thought!" Penny chuckled in delight. "Now we know how Rap Molberg escaped from the police the other night."
In fascination the girls watched the widening gap in the wall. Soon it was large enough for an automobile to easily drive through into the empty building.
"How did you open it?" Susan asked in awe.
"The beam of my spotlight struck a photo-electric cell which was secreted near the eaves," Penny explained briefly. "You should have read about it at the library."
"I wish I had now. It's almost uncanny."
"Let's drive in and have a look at the inside," Penny suggested daringly.
"Won't it be dangerous?" Susan demurred.
"The place seems to be deserted. But probably it would be wiser if you waited here and I went in alone."
"No, if you're going to risk it, so am I!"
"Then here goes," Penny said.
She drove the roadster through the opening into what appeared to be an empty room. Curiously, the girls glanced about. Suddenly Susan uttered a stifled scream.
"The door! It's closing!"
Already the opening had narrowed to a mere slit. It was too late to retreat.
"Don't lose your nerve," Penny advised, although her own heart was beating at a furious rate. "We'll find some way to open that door."
"Someone may have seen us drive in and closed it deliberately!"
"I don't think so, Susan. It must have closed automatically."
"Anyway, we're prisoners inside this horrible place! We'll starve to death before anyone will suspect we're here!"
"I got you into this and I'll get you out," Penny announced firmly. "There must be some button or lever that opens the door from the inside."
Although the headlights of the roadster illuminated a portion of the large room, many of the corners and crannies remained dark. Taking her flashlight from the pocket of the car, Penny moved cautiously about searching for some means of escape. Susan remained huddled in her seat, too terrified to move.
Penny examined the door, but it would not budge when she threw her weight against it. She could find no lock or catch.
There were several windows high overhead but without a ladder she could not hope to reach them. She was growing more disturbed than she cared to admit, when Susan called to her.
"Penny, I think there's some sort of lever over here by the car."
Penny flashed her beam in that direction and was relieved to see that her chum was right.
"It must operate the door, Susan! We should be out of here in a jiffy!"
Confidently, she grasped the long handle and pulled with all her strength upon the iron lever.
From below came the low rumble of moving machinery. Penny and Susan riveted their eyes hopefully upon the door. It did not open.
Instead, a square of floor upon which the roadster was resting, slowly began to sink.
Uttering a frightened scream, Susan tried to open the car door.
"Save me!" she cried frantically.
Penny leaped nimbly down upon the running board.
"It's all right," she laughed shakily. "We're only descending in an elevator."
"We'll be killed before we ever get out of this dreadful place!"
The elevator struck the lower floor with a gentle thud. Penny then climbed into the car and drove it a few feet forward. Relieved of its weight the platform slowly rose again until it had resumed its former position.
"We're worse off now than we were before," Susan moaned.
"I think this must be the way out," Penny comforted.
She indicated a tunnel-like opening directly ahead. Susan who had been looking in the opposite direction had noticed a small room which appeared to be an office. She called her chum's attention to it. Together, they cautiously peered inside.
Save for a battered desk and several chairs the tiny room was empty. Cigarette ashes and old papers were scattered over the floor, giving evidence that the office had been used recently. Penny tried the desk and found it locked.
She picked up a few scraps of paper from the floor. They were without interest.
A folded newspaper lying upon one of the chairs drew her attention. Opening it, she noticed that an article on the front page had been underscored with pencil lines. The headline read:
"AUTO ACCESSORY THEFTSON STEADY INCREASE HERE"
The story hinted that Belton City police had been unable to cope with the situation and that local insurance companies long harassed by an organized gang, had turned the case over to private detectives.
Above the latter statement someone had written the name of Christopher Nichols in pencil.
Penny carefully folded the newspaper, replacing it upon the chair exactly as she had found it.
"Let's get away from here before we're caught," she urged. "I suspect we're in a Molberg hideout."
"Nothing would please me better than to leave this place," Susan retorted grimly. "Just lead me to an exit."
"I think the tunnel probably will take us out. Come on, let's see."
Returning to the roadster the dark passage seemed forbiddingly dangerous. Carefully examining the concrete floor, Penny discovered tire patterns in the dirt. Other cars had used the tunnel.
With the engine at idling speed, they drove into it. The tunnel led downward at such a steep angle that soon Penny was forced to use her brakes to keep from going too fast.
"Where will this thing end?" Susan asked.
Even as she spoke they reached level ground. An ordinary double garage door barred the way. Susan sprang out to open it.
"Why, we're in an empty garage," she announced as she swung back the door.
Penny drove the roadster through and waited until Susan had closed the door behind her. Through a plateglass window the girls could now see the street. But it took them some time to locate another unlocked door which permitted them to escape.
Once safely out of the building, they pulled up at the side of the road to take note of their surroundings. At first they could not imagine where they were.
"Why, this must be Arlington Avenue," Penny decided. "We're several hundred feet lower than we were when we left that dead-end street on the hilltop!"
"What a clever means for a crook to escape a police chase!"
"Yes, isn't it? I'm almost certain the place has been used by the Molberg gang."
"Then we can't get away from here too quick," Susan declared nervously.
Penny laughed.
"We're safe enough now. Besides, I imagine this escape is never used except in an emergency—probably only when the police are hot on the trail."
Susan glanced at her watch.
"It's after ten o'clock and I promised mother I'd be back at nine."
"I'll take you straight home," Penny promised. "I don't suppose I need to mention it, but I think we shouldn't tell anyone about what we discovered tonight. At least not until the police have been notified."
"Of course not," Susan agreed instantly. "Why don't you have your father make the report for us?"
"I'd like to handle it that way, if you don't mind," Penny said eagerly.
"Then let's leave it that way. Aside from Mr. Nichols we'll not tell a soul about our discovery tonight."
A few minutes later the girls took leave of each other. Penny continued alone toward her own home.
Turning a corner in one of the outlying neighborhood business sections, she noticed a girl in blue hurrying along the street. Recognizing Betty Davis, Penny halted her roadster at the curbing.
The girl did not notice for she had paused to stare into the window of a café. A group of young men could be seen within, laughing and talking.
It was not the type of place frequented by women, and Penny was astonished when the girl started to open the door. But with her hand on the knob, Betty Davis seemed to reconsider, for she turned and walked rapidly away.
Penny drew alongside in her roadster.
"Going my way?" she asked cheerfully. "I'll be glad to give you a lift."
Betty Davis wheeled quickly about. She laughed to cover her confusion.
"Why, Miss Nichols! How you startled me!"
"I didn't mean to do that," Penny smiled. "If you're on your way home, can't I take you there in my car?"
The girl hesitated, and involuntarily, her eyes wandered toward the café. Then she stepped into the car.
"It's very kind of you to take me home, Miss Nichols. I'm not out alone this late in the evening as a rule, but something important came up. I searching for my brother."
"Jimmie?"
"Yes, how did you know?"
"I think your father mentioned his name."
"He didn't say anything about——" Betty broke off, finishing with an embarrassed laugh: "but then I know he didn't."
"Your father only mentioned that he had a son by that name," Penny said, eyeing her companion curiously.
"Jimmie is a good boy but he's caused father a great deal of worry," Betty added, feeling that some explanation was required. "Lately he's fallen in with bad companions."
"That is a pity," Penny murmured. "You mentioned that you were looking for him. Can't I help you?"
"Oh, no," Betty told her hastily, "I don't think I'll bother after all."
Penny permitted the matter to drop but she was not mistaken in suspecting that the reason her companion had decided to give up the search was because she already had located her brother at the café.
"Won't you come in for a few minutes?" Betty urged when the car stopped at her door. "Father isn't due home until late tonight and I'm all alone."
"I might stop a little while," Penny agreed.
Despite Betty's somewhat queer actions, she had liked the girl from the very first, and was eager to become better acquainted.
The Davis home was modestly furnished, yet with excellent taste. Penny could not refrain from referring to the clever color scheme which had been carried out so successfully in the living room.
"I'm glad you like it," Betty smiled. "You see, I'm studying to be an interior decorator."
"Why, how interesting."
"I attend night school," Betty explained. "Or rather I did. Just now Father is a little pressed for money so I've given it up for a few months."
"I hope you'll be able to go on with it again."
"Yes, so do I, for it's the one ambition of my life. I think after Jimmie is a little older it will be easier. Just now he's at the age where he feels he must have fine clothes and plenty of spending money."
"Perhaps you're too indulgent a sister," Penny smiled.
"Jimmie is only a year younger than I," Betty explained, "but since Mother died five years ago, I've always felt responsible for him. Lately I've been terribly worried."
"On account of the company he keeps?"
"Yes, that and other things." Betty arose and nervously crossed over to the fireplace. "I don't mean to unburden myself upon you, but lately Jimmie has been doing wild things. Father doesn't half suspect the truth. I'm half sick with trying to decide if I should tell him or not."
"Probably it would relieve your mind if you did," Penny advised kindly.
"Yes, but Father has always taken such pride in Jimmie. I can't bear to hurt him."
"Perhaps he could bring your brother to his senses."
"I'm afraid it may be almost too late. Jimmie is so headstrong. He won't listen to anyone. He's changed so much the last few months."
"It seems to me that your father should know the truth," Penny said quietly.
Betty Davis' face had grown slightly pale.
"I realize I should tell him," she acknowledged, "but I can't. There's a special reason why—don't ask me to explain." Abruptly, she tried to change the subject, saying lightly: "My brother is very handsome, I think. Would you care to see his photograph?"
"Indeed I would," Penny returned politely.
She waited while Betty went into an adjoining room after it. As the girl returned, a car was driving slowly past the house.
"That must be Father," Betty declared, moving toward the window.
Penny heard the automobile halt at the curbing. The next instant a hard object crashed through the windowpane, dropping with a thud at Betty's feet. Almost by a miracle she had escaped being struck by the flying splinters of glass.
Penny sprang to her feet, rushing to the door. She caught only a fleeting glimpse of the retreating car.
Betty was staring at a piece of paper which lay upon the carpet. It had been wrapped around a small stone.
"You read it," she begged Penny. "I'm afraid."
Penny reached down and picked it up. The message had been printed on cheap brown wrapping paper. It bore the warning:
"JEROME DAVIS, THIS IS THE LASTWARNING YOU WILL RECEIVE FROM US.WE GIVE YOU TWENTY-FOUR HOURS TOCHANGE YOUR MIND."
"It's a threat from the Molberg gang!" Betty declared tensely as Penny finished reading the message aloud. "Oh, I'll never feel easy again until every member of that outfit has been placed behind bars! What do you think they will do when Father defies them?"
"Probably nothing," Penny comforted. "Most anonymous notes are sent by cowards and the threats seldom carried out. At least Dad doesn't regard them very seriously. He's been threatened by the Molberg gang too."
"And have they made no attempt to harm him?" Betty asked.
"Not to my knowledge. Dad seems more than able to look after himself, and I'm certain your father knows how to protect himself too."
"He should," Betty admitted. "He's one of the best marksmen on the police force."
"Then I think Rap Molberg is the one who should be on his guard," Penny smiled.
By making light of the threatening note she tried to relieve Betty of anxiety. Her efforts were not very successful. When she left the house a half hour later the girl was still excited and overwrought.
Not until Penny was nearly home did it occur to her that she had forgotten to look at the photograph of Jimmie Davis.
"Oh, well, it doesn't matter," she thought.
As she drove the roadster into the garage, Mrs. Gallup came down the path to meet her.
"I'm sorry to be so late," Penny said quickly before the housekeeper could take her to task. "A million and one things detained me. Dad's home, I suppose?"
"No, he isn't. But someone has been trying to get you on the telephone for the past hour."
"Probably it was Dad."
"It may have been, but it didn't sound like his voice. Listen, isn't that the phone now?"
They could hear the bell ringing inside the house. Penny ran to answer it. As she took down the receiver, she was greeted by a masculine voice. But it was not the detective who had telephoned.
"Is this Miss Nichols?" she was asked.
"Yes," Penny returned quietly, aware from the other's tone that she must prepare herself for bad news.
"Don't be alarmed, Miss Nichols, but your father has been hurt."
"Oh! Badly?"
"We're not sure yet. He is still unconscious. Can you come at once?"
"Yes, yes, of course! Which hospital?"
"He has been taken to a private home."
"Then tell me how to get there."
"It won't be necessary. A taxi has already been sent for you. It should be there by this time."
"I'll be waiting," Penny promised.
She hung up the receiver and turned to the housekeeper who was hovering anxiously at her elbow.
"Dad's been hurt," she said tersely to hide her emotion. "I don't know how badly for I couldn't learn the details. I must go to him at once."
"Oh, you poor thing," Mrs. Gallup swept the trembling girl into her arms.
They clung to one another for an instant, then Penny resolutely brushed away her tears.
"It probably isn't as bad as we fear," she said hopefully.
Catching up her pocketbook from the table, she hurried out upon the porch to wait for the taxicab.