20 - The Hardy Boys: The Secret of the Caves by Franklin W Dixon

In The Hardy Boys: The Secret of the Caves, Frank and Joe Hardy embark on another thrilling mystery. After saving a drowning woman, they uncover a deeper mystery involving her missing brother. Their search takes them to a series of eerie caves, where danger and deception lurk in the shadows. With puzzles to solve and criminals to catch, can the Hardy Boys crack the case before it’s too late? A classic installment in the beloved detective series!