Overhearing

In several Agatha Christie stories the plot features someone overhearing a snatch of conversation. Subsequent events, or some deduction often depend on what was overheard. The significance of what was overheard may or may not be perceived by the listener immediately.

Stories where overhearing is used as a plot device

 * Murder on the Orient Express - Poirot overhears Mary Debenham saying to Colonel Arbuthnot: “Not now. Not now. When it's all over. When it's behind us—then-”
 * Appointment with Death - Poirot overhears Raymond Boynton saying to Carol Boynton: “You do see, don't you, that she's got to be killed?”
 * At Bertram's Hotel - Miss Marple overhears Bess Sedgwick talking to Micky Gorman.
 * The Clocks - Somebody overhears what Edna Brent says to Constable Pierce after an inquest. Edna is subsequently killed.