A town busybody is poisoned at a busy reception in the home of famous film star Marina Gregg. The poisoned drink seemed intended for Marina, but Miss Marple is not so sure. She sets out to discover the true identity of the killer before he or she can strike again.

Miss Marple, the spinster detective who is one of the most famous characters created by English crime writer Agatha Christie, is portrayed by Joan Hickson who starred in a dozen television mysteries about Miss Marple over the course of a decade.