Lieutenant Colin Race is investigating the death of two Navy personnel when a distraught Sheila Webb runs out of 19 Wilbraham Crescent and into arms. Poirot arrives in Dover to help Colin determine if Sheila is responsible for the murder of the middle aged man found stabbed no the sitting room floor. Sheila claims not to know the murdered man or the blind woman who owns the house, Miss Pebmarsh. Miss Pebmarsh was not at home when the murdered corpse was found denies having requested the secretarial services of Sheila by telephone earlier that day. Poirot observes the mounting complications to the case - the four clocks frozen at the time of thirteen minutes past four in the room where the body was found, an unidentified murder victim and a host of neighbours who don't seem to have seen anything. Colin is determined to find a connection with the recent death of his fiance and a German mole from within the Navy but in his state of grief he becomes increasingly involved with Sheila Webb. A wall of evidence begins to build against Sheila and the clock ticks for Poirot when another innocent victim is found brutally murdered.