Mystery film based on an Agatha Christie play. An ambassador's wife must hide the corpse of her stepdaughter's unlikeable stepfather from her husband, who is bringing important visitors to their country home.

Shuhei, a mystery writer, is invited to a dinner party at a country house. The guests include Tanase and his wife Noriko. Next day, Tanase is shot and Noriko with a gun stands near him. Tanase calls one of the guest's name and dies.