Bob stopped and stared in amazement. He could scarcely believe his eyes. There was the car that had disappeared so mysteriously the night before, in its right place, and undamaged as far as he could see.

"Heinrich," he exclaimed in amazement.

The chauffeur, a hose in one hand, a big sponge in the other, and wearing high rubber boots, looked up inquiringly.

"What are you doing up so early?" he asked.

"Where did the car come from?" demanded Bob.

Heinrich straightened up and gazed at Bob.

"What you mean?" he inquired.

"Who brought the car home?"

"How do I know? Maybe your father use it last night. Whoever do it, get it all covered mit dust."

"But," stammered Bob, "the car was stolen."

"What!" exclaimed Heinrich. "What you talking about?"

"What time did you get in last night?" Bob inquired, becoming more and more anxious and bewildered every moment.

"Twelve o'clock," said Heinrich. "What you mean the car iss stolen?"

"Was it here when you came home?"

"Certainly it was here. What you talking about?"

"I don't know," said Bob weakly, and he sat down on the running board and passed his hand across his brow.

"Are you sick?" asked Heinrich anxiously. "You look pale."

"I'm not sick," said Bob. "I guess I'm crazy," and he held his head in both hands, staring blankly at the floor.

Heinrich did not know what to make of the strange behavior of his employer's son. He stared at him curiously, and it was plain to see that he was telling the truth in all he said.

"What you mean the car iss stolen?" he inquired finally.

"Nothing," said Bob blankly. "It's too much for me."

"I go to a party last night," said Heinrich. "I come home late and the door here iss open. Here iss the car too. Why you think it stolen?"

"I don't know," said Bob. "I guess I must have dreamt it."

"You are sick," exclaimed Heinrich. "You had better go back and go to bed. If you wish I go with you to the house."

"No," said Bob. "I'm all right." He rose to his feet dazedly, looked in bewilderment at the car again and started out.

"I have a loss," said Heinrich, convinced that Bob was probably all right.

"What's that?" demanded Bob, turning around.

"Burglars," said Heinrich.

"Where? In the garage here?"

"Yes. Last night," and Heinrich brushed a tear from his eye.

"You did?" exclaimed Bob. "They didn't steal all that money you had yesterday, did they?"

"No," said Heinrich sorrowfully. "I almost wish they had. They steal Percy."

"Percy," cried Bob, greatly relieved. "Why should any one steal him?"

"I do not know. I come down this morning and I look in the tub to say good-morning to Percy. The tub iss here, but Percy iss gone."

"There are some queer things going on around here, Heinie," said Bob.

"I like to catch the man what steal him," said Heinrich fiercely.

"I'd like to catch lots of people," said Bob. "Maybe he fell out of the tub."

"He could not do that," exclaimed Heinrich. "The sides iss too high."

"Well, it's certainly strange." Bob went out of the garage and started slowly back toward the house. Heinrich, sorrowing over the loss of his alligator, with a sigh took up the sponge and hose again and fell to washing the car once more.

Bob returned to his room, washed his face and hands, something he had neglected to do before, and went downstairs again. He glanced at the morning newspaper, full of war news and preparations for war; one column told of the arrest of many Germans all over the country, men who were suspected of caring more for the Fatherland than they did for the United States.

There was no mention of the bomb episode on the railroad bridge the night before, however. Bob knew that the authorities would not permit the publication of any such items if they could prevent it so he was not surprised. Presently the rest of the family appeared and they went in to breakfast.

Mr. Cook's mail was lying on the table by his plate; it was his custom every morning to glance it over while he was eating. While Mrs. Cook talked to Bob about Harold, her husband looked through his letters. Suddenly he uttered an exclamation of surprise. "Here's a queer thing," he said.

"What?" demanded Mrs. Cook anxiously. She had been very nervous lately.

"This postcard," said Mr. Cook. "Listen to what it says. 'Take the advice of one who knows and keep your automobile home at night.'"

Bob turned pale. "What does it mean!" inquired Mrs. Cook.

"I'm sure I don't know," said her husband.

"How is it signed?"

"It is not signed at all."

"I can't imagine what it's all about," said Mr. Cook. "As far as I know, our car hasn't been out of the garage at night for over a week."

"Perhaps Heinrich has had it out," Mrs. Cook suggested.

"I'll ask him right after breakfast," said Mr. Cook. "They must have mistaken our car for some one else's."

"Who do you suppose sent it?"

"I'm sure I don't know," said her husband musingly. "At any rate I think
I shall turn it over to the police; I don't like the look of it."

Throughout this conversation Bob sat silent. He thought perhaps he could explain part of the mystery to his father, but he was puzzled as to whether he ought to do so or not. On the other hand if his father called in the police, he knew that he and Hugh would have small chance of clearing up the matter themselves.

"It worries me so, Robert," exclaimed Mrs. Cook. "I am so afraid that something will happen to you, especially as you are making war supplies at the factory now."

"The plant is guarded," said her husband. "Besides I think I owe it to my country to help all I can, don't you?"

"Of course, but suppose some of your guards are treacherous."

"They are all trusted employees of American birth."

"No Germans at all?"

"The man in charge at night has parents born in Germany; you know him, Karl Hoffmann, the one who wants to marry Lena. He is just as faithful and true as she is. I can vouch for all the others as well."

"He's all right I guess," said Mrs. Cook with a smile. "Even if Heinrich doesn't like him." Heinrich and Karl Hoffmann were rivals for Lena's affections, and they despised each other. Lena, however, seemed to like them both equally well, or at least she did not care enough about either to marry him.

Bob used to delight in teasing Heinrich about his rival. When Karl was on the premises Heinrich would sulk in the garage and mutter threats against him. Karl was twice Heinrich's size, but the little blue-eyed, spectacled chauffeur never seemed to question his ability to deal with him.

Mr. Cook rose from the table. "I'll go down and ask Heinrich about this car business," he said, "and then I'll go down to the office." He kissed Mrs. Cook and Louise and left the room. Bob followed him out. His father put on his coat and hat and stepped out onto the front porch. A sudden resolution seized Bob.

"Father," he said.

"What is it, Bob?" asked Mr. Cook, turning to glance at his son.

"I think I can explain about the car."

"You can?" exclaimed his father in surprise, looking curiously at Bob's pale face.

"Yes, sir," said Bob, nervously. "It's a sort of a long story. Shall I tell it all?"

"Certainly. Come out here to the summer house."

They walked in silence to the little rustic house on the lawn and sat down side by side on the rough wooden seat. Bob was excited, but still determined that the best thing for him to do was to tell his father the whole story. He knew his father would understand and see things from his point of view; they were more like two brothers than a father and son.

"Hugh and I had the car out last night," said Bob, and then he began at the beginning and related the entire story through to the end. He told of their visit to the armory, their meeting with Harold on the bridge, the narrow escape with the bomb, their decision to watch the Wernbergs' house, their trip to the deserted house, the disappearance of the automobile, and finally its strange return.

Mr. Cook listened intently throughout the whole narrative, one exclamation as Bob told of the bomb episode being his sole interruption.

"That card must have been sent by the one that brought the car back," said Bob.

"It would seem so," his father agreed, and fell silent, thinking.

"That was a close call you boys had with that bomb," he said finally.

"Yes, sir," said Bob.

"What have you planned to do to-day?"

"We were going to report the loss of the car to police headquarters and then go out to the deserted house again, to see what we could find."

"You weren't going to say anything to the police about it?"

"No, sir."

"That might be dangerous, you know."

"Yes, sir," said Bob. "We wanted to solve the thing ourselves if we could though."

"I don't know about that," said Mr. Cook musingly. "I hate to think of you two boys fooling around out there with a lot of desperate men around."

"Don't do anything until this afternoon anyway," Bob pleaded.

Mr. Cook thought for a minute. "All right," he agreed. "Ill wait until after luncheon. Do you and Hugh expect to go out there this morning?"

"Yes, sir."

"Have you got a gun?"

"No, we haven't."

"Well, there's an automatic pistol and two boxes of cartridges in the second drawer of my bureau. Go up and get them before you start, for I think you ought to be armed. And above all don't say anything about it to your mother."

"Certainly not," exclaimed Bob, much excited that his father was helping them.

"Be careful," warned his father. "I'll be home for luncheon and we'll talk more then."

Heinrich appeared with the car and Mr. Cook got in and was soon on the way to his office. Bob hurried into the house to telephone to Hugh and possess himself of his father's automatic pistol.

Hugh promised to hurry over as fast as he could, and he could tell from the tone of Bob's voice that something stirring was on foot. Bob had answered his question about the car evasively and he was anxious to hear the latest developments. Consequently by the time that Bob had tucked the pistol safely in his back pocket and had gone to the garage for his bicycle, Hugh appeared.

Bob related the story of the car and its strange return, and also told about the postal card his father had received that morning. The mystery seemed to deepen rather than clear up, and both boys were profoundly mystified by the strange events of the previous day.

"Your eye's better anyway," remarked Hugh.

"Yes," said Bob. "But I may get another one to-day."

"We'll hope not. When do you want to start?''

"Right away."

"Come ahead then," and jumping on their bicycles the two boys pedalled out of the yard. Little did they dream that bright April morning, as they rode along, that they were headed for adventures which would make the events that had gone before appear mild in comparison.