holiday for this purpose? All those engagements you have—all the fun you have planned with your young friends? Christmas Day alone in a strange city? Would it be worth it to you?”

It did not take Mary Louise a moment to make her decision.

“I’d love it, Dad!” she cried ecstatically. “But I shouldn’t know how to go about it,” she added hesitatingly. “What to do—how to begin.”

“Mrs. Hilliard—she is the hotel manager—would give you all the facts,” explained her father. “I’d go with you and get you started. But you must consider carefully, Mary Lou. Think of your friends and your mother and your own pleasures. You can let me know tomorrow.”

Mary Louise nodded solemnly.

“I know, Daddy. But this seems like the chance of a lifetime. Because you see I mean to be a detective when I graduate from high school. This is something definite to go on—a real experience, which I can make use of when I apply for a job.”

“Yes, of course. And, by the way, there is a salary attached. You are to get twenty-five dollars a week, and an extra bonus if you get any of the lost valuables back.”

“Oh, Daddy!” The exclamation was almost a whisper, so awed was Mary Louise at the thought of actually earning money in the work that she loved best in all the world.

“When would I start?” she asked.

“I could take you with me to Philadelphia tomorrow morning. But that wouldn’t give you much time to write notes to your friends and pack your things. I suppose you’d have a lot of engagements to break.”

“Yes, but they don’t matter.”

“Don’t you want to think it over another day? I could come back and take you after the weekend.”

“No, Daddy, there’s not a question of doubt in my mind. I want to try it and start as soon as possible. Some of the crowd will be at Jane’s tonight, and I can tell them and phone to the others. I’ll pack my clothes before I go. Have you told Mother yet?”

“No, I haven’t. I thought there was no use stirring her up if you didn’t care to undertake it. But now we’ll have to break the news to her, if you’re sure.”

“You tell her, Daddy!” urged Mary Louise. “It will be easier.”

“All right, I will,” he promised.

A voice sounded from the kitchen. “Mary Louise, could you do an errand for me? You’ll just have time before supper.”

“Yes, Mother,” replied the girl, jumping to her feet. Then in a whisper to her father she added, “Tell her while I’m gone.”

Picking up her coat again, she ran out into the kitchen.

“I want you to take this basket of jellies and fruit cake over to old Mrs. Detweiler,” said Mrs. Gay. “I think it would be nice for them to have the things earlier this year, because they have so little at Christmas time.”

“Yes it would, Mother,” agreed the girl absently.

“Ask them whether they’ve heard anything from Margaret,” added Mrs. Gay. “Maybe she’s coming home for Christmas.”

“She wasn’t home all summer, was she, Mother?”

“No. And they didn’t hear from her, either. They’re terribly worried. I can’t see why Margaret Detweiler would do a thing like that, when her grandparents have been so good to her all her life. Why, Mrs. Detweiler wore the same dress for five years just so she could put Margaret through high school. And the girl always seemed so grateful and affectionate, too.”

“Maybe something happened to her,” suggested Mary Louise.

“Surely they would have heard if it had.... Well, run along, dear. And come right back, because dinner is practically ready.”

Mary Louise pulled on her beret and her goloshes and went out into the snow again. It was entirely dark now, but the stars were shining, and the air was just cold enough to be invigorating. How good it was to be young and lively and happy! How sorry she felt for this poor old couple whom she was visiting, missing their granddaughter so dreadfully. But perhaps everything was all right. Maybe Margaret Detweiler was coming home for Christmas.

The small brick house where the old couple lived was only a few blocks from Mary Louise’s home. Half walking, half running, the girl covered the distance in less than ten minutes. She saw a low light in the living room and knocked at the door.

Both of the Detweilers were well over seventy, and they lived modestly but comfortably on a small pension which Mr. Detweiler received. It had been sufficient for their needs until the death of Margaret’s parents obliged them to take care of their only grandchild. But they had gladly sacrificed everything to give Margaret an education and a happy girlhood. She was older than Mary Louise by three or four years, so that the latter had never known her well. But she had always seemed like a sweet girl.

Mr. Detweiler opened the door and insisted that Mary Louise come inside. Both the old people loved Mrs. Gay and enjoyed the wonderful presents of her own making she sent every Christmas. They were profuse in their thanks.

“You must take off your things and get warm before you start out again,” urged Mrs. Detweiler.

“I’m really not a bit cold,” replied Mary Louise. “And Mother told me to come right back, as supper will be waiting. But she wanted me to ask you whether you had heard anything from Margaret.”

Tears came to the old lady’s eyes, and she shook her head.

“Not a thing since last Christmas,” she answered sadly. “You know she didn’t come home then, but she wrote to us and sent us a box of lovely presents. Expensive things, so I knew she must be doing well. She had a position in a Harrisburg store at first, you know, and then she told us she had gotten a fine job in a Philadelphia store. That was where the last letter came from—the last we ever received from her!”

“Didn’t you write to her?” asked Mary Louise.

“Yes, of course we did. But the letter was returned to us.”

“What store was she working in? I am going to Philadelphia for the Christmas holidays, and I might be able to find her.”

“I’m not sure. But the package was marked ‘Strawbridge and Clothier’ on the box. Did you ever hear of that store?”

“Yes, I did. And I’ll go there and make inquiries for you, Mrs. Detweiler.”

The old lady seized Mary Louise’s hand gratefully.

“Oh, if you could only find her, Mary Louise,” she exclaimed, “we’d be the happiest couple alive!”

“I’ll do the best I can,” promised the girl as she turned to the door.

She ran all the way home, eager to find out what her mother was going to say in reply to her father’s startling proposition about her Christmas vacation.

CHAPTER II
The Job

If Mrs. Gay did not like the idea of losing her daughter for two weeks, at least she kept the feeling to herself. She congratulated Mary Louise heartily on being chosen for a difficult piece of work.

“You’re a lucky girl!” cried Freckles, Mary Louise’s young brother. “Wish I was old enough to take the job!”

“You couldn’t take this one, Son,” his father reminded him, “because it’s a woman’s job. A man would be out of place in a woman’s hotel. But Mary Lou can go about unnoticed—people will think she’s just a guest.”

“Twenty-five bucks a week!” repeated Freckles. “What are you going to do with all that money, Sis?”

“I don’t know. Wait and see if I earn it. But if I do, we’ll all have something nice