Hugh was going home for dinner, and was to return shortly afterward to accompany Bob and his father to the factory. He left the house and Bob started upstairs to prepare himself for the evening meal. On the landing of the stairs he heard some one talking over the telephone and stopped to listen. Of late he had become suspicious of every one and had fallen into the habit of noticing every little thing that happened.

It was the cook's voice and he was doubly interested at once.

"Yes," he heard her say, "this is Lena."

Bob flattened himself against the wall and listened intently.

"What's that?" Lena demanded over the 'phone. "In the hospital, you say!"

There was a pause while the other person talked to her.

"I will try to be there," said Lena. "I also have a message for you, but I don't know whether I should say it now or not; those blamed detectives are on to us."

There ensued another pause while Bob became more and more excited. What was this plot anyway that turned old and trusted servants against their masters? Was no one to be relied upon? Who could be trusted?

"Yes, I will tell Heinrich," said Lena speaking again. "Good-by."

She hung up the receiver and Bob continued up the stairs, whistling and trying to act as if he had heard nothing. He met Lena in the hall and she eyed him narrowly.

"Hello, Lena," he exclaimed cheerfully. "Fine day, isn't it?"

"Yes, Mr. Bob," she said, and passed on toward the back stairs.

No sooner was she gone than Bob turned and sped down stairs again to the library. He burst into the room breathlessly, causing his father, who was reading his evening paper to glance up in surprise.

"Father," exclaimed Bob in a tense whisper, "Lena's in it too."

"What's that?" demanded his father. "Sit down, Bob."

Bob grasped a chair and sat down facing his father. "Lena's in it too," he repeated.

"In what?"

"In the plot with Mr. Wernberg."

Mr. Cook laid down his paper. "Tell me what you know," he said soberly.

Bob repeated the part of Lena's telephone conversation that he had heard. "You see," he exclaimed, "she spoke about the hospital and that must have meant Mr. Wernberg; then she said the detectives were on to them; finally she said she'd tell Heinrich and also try to be there to-night."

"You don't know what she is to tell Heinrich and where she is to be to-night?"

"No, sir," said Bob. "That's all I heard."

"Well," exclaimed Mr. Cook after a moment's pause. "This is a nice state of affairs."

"What are you going to do about it?" asked Bob. "Are you still going to wait until to-morrow before you report Heinie to the police?"

Mr. Cook passed his hand across his brow as if to wipe away the doubts that assailed him. "Heinrich and Lena both," he muttered. "What a pity."

"I tell you what I'll do," he exclaimed finally. "I'll take Heinrich along with me to-night just as I planned, and I'll tell your mother under no conditions to let Lena go out this evening. In the morning we may know better what to do."

"I have a better scheme than that," said Bob eagerly.

"Tell me what it is."

"Take Heinrich along with you and watch him all the time; that part is all right. But let Lena go out if she wants to."

"What's the point of that?" demanded his father. "For all we know Lena may he able to do more harm than Heinrich; certainly she's smarter."

"Let her go out," said Bob, "and I'll go with her."

"I don't see what you mean."

"I'll follow her."

"You'd have to be disguised."

"I know it; I'll attend to that though."

"It might lead you to some very dangerous spot," said Mr. Cook. "I hate to have you do it."

"Look here, father," exclaimed Bob earnestly. "We're at war with Germany, aren't we? Well, just think of all those millions of men over in Europe on the battlefields; all the English and French, and Italians, and Belgians, and Russians, and all the others. If the United States is in the war we ought to be willing to do our part. Our allies in Europe are fighting for us as much as for themselves, and it seems to me that to disguise myself and follow the cook is a small thing for me to contribute to the common cause."

"I guess you're right, Bob," said his father.

"Why look here," continued Bob. "Just think of the way those men over there are every one of them risking their lives a hundred times a day. We just can't sit still and let them do all our fighting for us. We can give them money and food and I think we ought to expect to give our lives too if it is necessary. I know I don't want to hide behind somebody else and let him fight for me."

"You're all right, my boy," exclaimed Mr. Cook, rising to his feet. He grasped his son affectionately by the arm, and there were tears in his eyes as he did so. "You're all right," he repeated, "and I'm proud of you. You've got the spirit that every true American should have, and which I believe they do have. When Germany finds herself facing a million American troops and sees the Stars and Stripes floating from the opposing trenches she'll know she's beaten. I hope we'll show them that we mean business and the sooner we do, the quicker the war will be over."

"What kind of a disguise can I wear?" asked Bob.

"I guess you won't need a very elaborate one. Isn't there a false-face in the house with whiskers or a mustache on it!"

"I think there is one I used last hallowe'en."

"Get that then," said his father. "We can rip off the whiskers and glue them on your face. Put on an old suit of clothes and a sweater; wear a slouch hat and take along that hickory cane that I have. That ought to fix you up all right."

"I guess it will," exclaimed Bob, much excited at the prospect. "I'll go upstairs and look for the false-face now."

"Don't put it on until after dinner."

"I won't," said Bob as he hurried up to the attic in search of the disguise he was to wear. In a cupboard on the top floor he found the false-face and quickly tore the whiskers and mustache from it. He brought the handful of hair down to his room and hid it in his closet. He selected the oldest suit he owned and placed it on a chair with an old slouch hat he used to wear when he went fishing.

The announcement that dinner was ready put an end to any further preparations for the time being. The meal was a quiet one and there was but little conversation. Mrs. Cook's thoughts were of Harold and she was greatly worried about him; particularly as she did not know where his regiment had been sent. Mr. Cook, although he too was concerned about his elder son, was occupied principally with anxiety as to the plots that seemed to be brewing all about him, and the possible damage to his factory. Bob, needless to say, was highly excited over the prospects of adventure that the evening held forth for him.

Finally dinner was over. Mr. Cook dispatched Bob to the garage with a message to Heinrich to have the car ready in half an hour. As Bob ran across the lawn he met Lena returning from the garage. "Aha," he thought as he greeted her, "you saw Heinrich all right, didn't you?" He was fully convinced now that their cook and chauffeur were agents of Mr. Wernberg, and partners in crime. A moment later he reached the garage.

"Father wants you to bring the car around in half an hour," he announced to Heinrich, who was engaged in putting on a clean collar and necktie.

"What!" exclaimed Heinrich angrily. Bob had never before seen their chauffeur question any order that his father had given. "I can't."

"Those are his orders," said Bob, eyeing Heinrich closely.

"Does he want me to drive him out?"

"He does."

"But I can't," cried Heinrich. "I can't, I tell you; I have an appointment."

"I guess you'll have to break it then," was Bob's retort.

Heinrich wrung his hands in desperation. "What shall I do?" he moaned.
"What shall I do?"

"Can't you change your appointment?"

"I do not think so," wailed Heinrich. "This iss terrible. Do you think your father would change his mind if I should speak to him?"

"I'm sure he wouldn't," said Bob. "I know he wants the car and he wants you to drive it. I heard him say that positively."

"This iss terrible," repeated Heinrich. "What will they do mitout me?"

"Who?"

"My friends."

"It's too bad," said Bob, more convinced every moment that mischief was afoot that evening. "I don't know what you can do about it though."

"Of course I have to go mit your father," said Heinrich finally, heaving a great sigh. "I wonder if he will want the car for long."

"I think he will."

"Very well," said Heinrich, becoming resigned to his fate, "I will be there but only because I do not wish to lose my job. But I fear something will happen."

"That's just what we want to prevent," thought Bob grimly. "All right then, Heinie," he said aloud. "Father will expect you in half an hour."

He hurried back to the house, warned his father that he should keep Heinrich always within sight, and related his conversation with the chauffeur as an argument for this course. Then he went upstairs, two steps at a time to make ready his disguise. While he was there Hugh arrived and went up to Bob's room.

"What are you doing, Bob?" he demanded.

"Putting on a disguise."

"What for?"

Bob told him.

"I want to go with you," exclaimed Hugh eagerly. "Two would be better than one anyway."

"Where are you going to get a disguise?"

"I'll borrow part of yours. You can certainly spare enough of those whiskers to make me a mustache anyway."

"You ought to have another hat."

"You can lend me an old cap, can't you? I've got on the oldest suit I own."

Bob brought out the glue pot and with Hugh's assistance was soon adorned with a set of black whiskers and a mustache. His hair did not match at all, but as he expected to wear a hat pulled far down over his eyes that fact did not make much difference. He put on the hat, and wearing his old clothes and a sweater looked at himself in the mirror.

"Whew," he exclaimed, "I'm certainly a hard looking character."

"You certainly are," agreed Hugh, "and you look about forty years old."

"All the better," said Bob. "Now let's get you fixed up."

With what was left of Bob's whiskers a small black mustache was twisted into shape and glued to Hugh's upper lip. It was remarkable to see what a great change in his appearance it made.

"When we take these things off, all the skin on our faces will come too," said Hugh inspecting himself in the mirror.

"Don't you care," exclaimed Bob. "What we're interested in at present is to have them stay on to-night. How about a hat for you now?" He rummaged around on the closet shelf and produced an old cap and a derby.

"Put the derby on, Hugh," he urged. "You'll look just like Charlie
Chaplin."

"That wouldn't do, I'm afraid," laughed Hugh. "I'd have too big a crowd following me."

"Turn up the ends of your mustache and you'll look like the kaiser."

"Not for me!" exclaimed Hugh hastily. "I don't want to look like anything German. I'll wear the cap, I guess. I think that's better than the derby."

At that moment Mr. Cook appeared upon the scene. He stood and looked at the two boys approvingly. "Well," he said, "you certainly look like a couple of tough customers all right. I'm glad you're going along, Hugh; I think two will be better than one."

"Is Lena still here?" asked Bob.

"Still here," said his father. "She's getting ready to leave though and you two had better be prepared."

"Where's Heinrich?"

"He's due in about five minutes."

"You'd better watch him, father," warned Bob.

"Don't worry about that," said Mr. Cook soberly. "I suppose that you two 'things' will come to the factory later. I expect to be there all night."

"We'll try to get there," said Bob. "We'll keep track of Lena as long as we can, and if it's possible we'll report to you at the office."

"Good," exclaimed Mr. Cook. "Don't forget to be very careful, and don't get into trouble if you can help it."

"We'll do our best," Bob promised.