The green-fingered amateur detectives work on a garden for an open-air theatre, where Rosemary's cousin is due to perform. However, the production suffers a setback when an actor shoots himself during rehearsal - and the gun is found to have contained live bullets instead of blanks. A member of the cast gets an attack of stage fright, and Laura is obliged to take her place in the play as the duo try to find the culprit.