The secret of the old mill

by Franklin W. Dixon

"It's getting to be a little too much. As dad said, it was adding insult to injury—tricking mother to the extent of eight hundred dollars and now sending an impudent note like that. It's up to us to use what we know."

"You mean to see if we can find out anything more about the mill?"

"I mean to find out everything there is to be found out about it."

"I'm with you. When do we start?"

"When should we?"

"To-night."

"So soon?"

"Why not?"

"It's all right with me."

"If we're going to go back there at all we may as well get it over with as soon as we can," said Frank. "I've been thinking over a way to get away with it and I think we should be able to get inside that place and investigate it without much trouble."