The Secret of the Old Clock is the first book in the Nancy Drew Mystery Stories series. Written by Carolyn Keene, this cozy antique mystery book follows the adventures of Nancy Drew, a young detective with a knack for solving puzzles. In this thrilling tale, Nancy uncovers a hidden treasure while investigating the mysterious disappearance of a wealthy woman's will. With its charming vintage setting and clever plot twists, The Secret of the Old Clock is a must-read for fans of cozy mysteries and antique enthusiasts.