While trying to unmask a mole at Dover's military base, Lt. Colin Race (Tom Burke, The Libertine) enlists Poirot to help him aid a pretty secretary apparently framed for murder. Called to a residence on a quiet street for a temporary typing job, she found only a man's corpse lying on the floor. No one can identify the body, find a murder weapon, or explain the presence of four strange clocks--none of which belongs in the home, and all of which stopped at 4:13.