David and Sally, young detectives from Knowre School, embark on a field trip to the Greylock Clock Museum. After a mysterious bus incident, they explore the museum, where an eerie, cursed clock catches their eye. When the clock goes missing after a power outage, they follow clues to a warehouse filled with stolen artifacts and help police catch the thieves. Their adventure deepens when the museum tour guide reveals a secret society's sinister plans involving the clocks. During a midnight stakeout, David and Sally uncover the society's ritual and alert the police, who arrest the members. Following more clues to an abandoned mansion, they confront the society's leader, learning of a plot to harness the clocks' powers. With the authorities' help, they raid the mansion, defeat society, and restore peace. David and Sally leave Camp Greylock triumphant, ready for future mysteries and adventures together.