"Yes, my sister's handkerchief proves that," agreed his chum. "Now we must go back to the others."
"But Grace and Mollie will have a fit when they know we haven't found Betty and Amy."
"It can't be helped. There has been some mix-up somewhere. I have an idea, but I won't spring it now. Come on."
They hurried back to where the motor boat had been left.
"Were they there?" asked Grace, eagerly.
"Yes, they—were," said Allen, slowly. "But they've gone home."
"How do you know that?" asked Henry in a low voice.
"I don't know it!" came the reply in a whisper. "But we've got to pretend that until we find it isn't so. I'm hoping it is, though. You see," he went on, aloud, "we found they had been there. Amy dropped her handkerchief."
"But where are they now?" demanded Mollie.
"They probably hurried back to the cottage."