The Secret of the Old Clock is a cozy antique mystery book written by Carolyn Keene. Set in the 1930s, the story follows Nancy Drew, a young detective, as she investigates the disappearance of a valuable antique clock. With her keen eye for detail and determination, Nancy uncovers a web of secrets and uncovers the truth behind the old clock. This cozy mystery is filled with charming characters, intricate puzzles, and a nostalgic atmosphere that will transport readers back in time.