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...