Superintendent Spence informs Hercule Poirot of the case of Mrs McGinty, an elderly charwoman, apparently killed by her lodger, James Bentley, for her savings of £30, which she kept under a floorboard.
Bentley is convicted and to be executed for the crime, but Spence does not think he is guilty.
Poirot agrees to go to the town of Broadhinny and investigate the murder further.
Poirot finds that Mrs McGinty often worked as a cleaner at the houses of people in the village.
No one wants to talk to Poirot, and most believe Bentley is the killer