Hercule Poirot finds himself investigating the murder of his dinner host, Mr. Shaitana, who was stabbed in the heart while his guests played bridge. There are eight guests and Poirot finds himself in the company of three other investigators. The foursome interview each of the other guests in turn but make little headway until Poirot manages to reconstruct the various bridge hands played at the suspects' table. In doing so, he is able to identify one particular action that leads him to identify the killer.