Directed by: George Pollock
Starring: Leo Genn, Shirley Eaton, Fabian, Hugh O'Brian
Hugh Lombard: Drop dead.
Det. William Henry Blore: That's not funny.
Judge Arthur Cannon: I find it a singular lapse of manners - a house party, and the host the last to arrive.
Mike Raven: It happens.
Judge Arthur Cannon: Not to me, young man.
Ilona Bergen: How utterly marvelous! You all came to a house party without knowing your host.
Hugh Lombard: Well, what about you, Miss Bergen?
Ilona Bergen: Darling, it happens to me all the time.
Continuity mistake: Mario Adorf is walking in the hallway at the beginning, to the right, towards a large vase. The camera is on the stairs, and the vase casts a shadow to the right. In the middle shot that follows, the vase casts a shadow to the left and half of the space is taken by a shadow cast by the column that was completely absent earlier. (00:03:05)
Trivia: The voice of the mysterious host U.N. Owen is an uncredited Christopher Lee. (00:15:20)