When Clive Trevelyan, a Member of Parliament and war hero, is murdered, Miss Marple sets out to solve the case. Trevelyan had made his fortune years before in Egypt by secretly uncovering a lost tomb. He was killed during a major snowstorm when there were no police available. Several possible suspects emerge, including Trevelyan's ward, James Pearson and his fiancée Emily Trefusis; his political agent, John Enderby; a journalist Charles Burnaby; a visiting American, Martin Zimmerman; and several other parties seemingly uninterested in the matter. A convict has also escaped from Dartmoor prison. Miss Marple deduces that the murder is related to Trevelyan's days in Egypt and begins to identify the culprit.