“Do what?” asked Mabel.
“Try to find the ghost of the old mill—or whoever is hiding there.”
“Do you think some one is hiding there?” inquired Marie.
“There must be—to take the boys’ things. And they said they made a good search all over the mill this morning, after they discovered their loss. They couldn’t find a trace, though.”
“Then how can we?” asked Alice.
“We have better luck,” went on Natalie. “Look how we found the Gypsy camp. Besides, I have a theory.”
“What about?” Mrs. Bonnell wanted to know.
“About the hiding-place of the ghost. I think there must be a secret room in the old mill. There almost always was, in old colonial houses, you know.”
“And what makes you think some one is hiding there?” asked Mabel.
“Because of the way the boys’ things disappeared. Why, listen! Maybe some criminal is hiding in the old mill, and only dares come out at night.”