counter. "Hot day, eh?" he said, as the boys reached for straws.
"You bet it's hot." After a satisfying gurgle of the ice-cold pop, the Hardy boys turned to their chums. "We have a clue," declared Frank.
"About what?"
"About Chet and Biff."
"Yes?" Tony and Phil were immediately interested. "What's up?"
Frank then told them of the incident of the letter and, often prompted by his brother, explained how they had connected it with the disappearance of their chums.
"And so," he concluded, "we've figured that Chet and Biff may have been kidnapped in mistake for us."
"There's something in that, too," agreed Phil. "And here's something else that may help. I forgot about it when we were searching for the fellows the other day. Just a little while before they went on their trip I was talking to Chet and Biff and I remember that Biff said he had always wanted to visit Blacksnake Island."
"Blacksnake Island!" exclaimed Frank. "That's the place that is overrun with big blacksnakes, isn't it? Nobody ever goes there."
"That's the place, and that's why it's called
