This is the original 1929 story of The Secret of the Caves: The Hardy Boys book 7. The book has undergone one major revision since originally published in 1929, resulting in two different stories bearing the same title.

While enjoying a summer day boating on Barmet Bay, Frank and Joe end up saving Mary Todd from downing. She was on her way to see their father, Fenton Hardy about the mysterious disappearance of her brother. While Fenton Hardy went to search for him, Frank and Joe discovered a few small details about the missing professor. Fenton Hardy returned after his unsuccessful search as the boys were heading to a camping trip with Chet and Biff to Honeycomb Caves. They hoped to find treasure. Instead, they found life-threatening danger plus the criminal Carl Schaum and the maniac Captain Royal. Although they didn't want to be found, they needed it! The four chums succeeded and in the end the secret was kept. The four chums all received rewards for their great work.

Much has changed in America since 1929. The modern reader may be delighted with the warmth and innocence of the characters; but uncomfortable with the racial, social, sexist terms and stereotypes. As such, this book is a part of our heritage, a window into our real past.