During a train journey, Miss Marple witnesses how a young woman is strangled, when a curtain suddenly pops up in a passenger window of the train traveling on the parallel track. The local police can not find any evidence to support her story and conclude that the old lady has mixed reality with all the detective stories she has read.
  
 Of course, the stubborn Miss Marple cannot accept this and she therefore begins to conduct her own investigation with the help of her faithful friend Jim Stringer. They conclude that the body must have been thrown by the train near Ackenthorpe Hall's estates, which border the railway track. Miss Marple is therefore looking for work as a housekeeper at Ackenthorpe Hall to be able to look for the missing dead body and solve the mystery.