When Clive Trevelyan - Member of Parliament, war hero and heir apparent to Prime Minister Winston Churchill- is killed, Miss Marple sets about to solve the case. Trevelyan has made his fortune many years before in Egypt having secretly uncovered a lost tomb. He is killed during a major snowstorm when there are no police available. There are several possible suspects including Trevelyan's ward, James Pearson and his fiance Emily Trefusis; his political agent, John Enderby; a journalist Charles Burnaby; a visiting American Martin Zimmerman; and several other apparently disinterested parties. A convict has also escaped from Dartmoor prison. Miss Marple concludes that Trevalyan's murder is related to his days in Egypt and sets about to identify the murderer.