"It was simple enough," replied the young man. "It appears that the corner of the document, describing the birth mark on my sister, was torn off when the firm I have engaged to help search for her, forwarded it to me. One of the stenographers found it in her desk the other day, and they sent it on. "I had some business in this section, so, remembering your kind invitation to spend some time in your camp, I decided to avail myself of it, and stop over." "Glad you did," said Will hospitably. "Did the storm bother you?" "Not much. You were caught in it though." "Yes. Had to leave the ice boat and tramp back. But we're all right now. We'll hustle around and get some grub," announced Allen. "Then we'll go over and see the girls. They'll be anxious to hear the story. You haven't succeeded in locating your sister yet; have you?" "No, I've been on a number of false trails, but I somehow feel that luck is going to turn now." Mr. Blackford, who said he had been invited by Mr. Franklin to make himself at home in the cabin of the boys, turned in and helped them get ready a simple meal. It was now night, and the boys were tired out from buffeting the storm. But they were in good spirits, and glad to see their friend. After the meal, at which all present displayed good appetites, they went over to the girls' cabin, where they found Betty and her chums in dry clothes sitting before a roaring fire. "My, this looks like all the comforts of home!" exclaimed Mr. Blackford approaching the blaze and rubbing his hands. "You certainly have it fine here!" "So you have good news?" queried Grace, for Will had slipped over for a moment to give a hint of what was to come. "Yes, I have a description of my sister's birth mark now. So if you see her--or if I do--we can identify her." "I hope we do find her," spoke Betty sympathetically. "What sort of a mark is it?" "It is the letter 'V' on her left arm, just above the elbow," returned Mr. Blackford. "That ought to be easy to see--especially in summer time when the girls wear short sleeves," said Will. "But in winter it would be rather awkward going about asking a girl if she had the letter 'V' tattooed on her elbow. She might think you were trying to jolly her." "It isn't a tattoo mark," said Mr. Blackford, as he consulted the description, the torn-off piece having been pasted on to make it complete. "It's a red birth-mark, this paper says, and is in the shape of a 'V'. I do hope it will lead to something. If you girls----" "Why--why!" cried Betty springing to her feet. "Amy, you have a mark like that--at least it looks like a mark on your arm. I have often seen it!" Betty was much excited, and Amy turned pale. "Is this--is this so?" faltered Mr. Blackford eagerly. "Have you such a mark?" "Not such as you describe," replied Amy with a blush. When the young man had first spoken of a birth mark a rush of hope had flooded her heart. Now it had receded, leaving her disappointed.