Film star Mae Feather is in the studio shooting a scene from a romantic western titled Prairie Love with her husband and co-star Julian Gordon. Mae storms off after an argument, and passes a neighbouring set, where comedy star Andy Wilks is filming a slapstick scene. Mae is in love with Andy and her marriage to Julian is unhappy. A visiting reporter, Asphodel Smythe of Flicker magazine, introduces herself and is granted an interview in Mae's dressing room; Mae presents herself and Julian as a perfect couple. Outside, a group of studio technicians and extras make fun of Mae's diva-like behaviour and their gossip implies she is having an affair with Andy. After the interview, Andy asks Julian if he can escort Mae to the theatre.

Mae and Andy do not go to the theatre, instead spending the evening together at Andy's flat. A neon sign outside the window advertises Mae's latest film My Man. They discuss Andy's imminent move to Hollywood, and share a passionate kiss. Meanwhile, Julian has gone to the cinema to see My Man, a potboiler in which his character rescues Mae's from a dastardly villain and they live happily ever after. Having given Andy her door key, Mae leaves his flat and comes home to find Julian polishing his shotgun; as he jokingly 'shoots' her lipstick through one of the barrels she begins to hatch a plan to get rid of him.

The next day, Andy is filming on location at the beach, while two reporters hidden on a cliff-top spy on proceedings through binoculars. A stunt double dressed like Andy is injured during filming and one of the spies rushes off to report what he thinks is Andy's demise. Mae signs a new contract to go to Hollywood, and notices a clause forbidding any scandal in her personal life. At home, Julian returns unexpectedly and Mae frets that Andy will let himself in while he is there. The wireless brings false news of Andy's accident, but soon after Andy lets himself into the flat and Mae is so relieved to see him safe and well that she lets her guard down and Julian witnesses them kissing. Julian throws Andy out, while Mae pleads with him for the sake of her career.

At the studio, the climactic scene of Prairie Love is being prepared, in which the villain is to shoot Julian with a dummy bullet. Mae sneaks a real bullet stolen from Julian into one of the barrels of the shotgun. Filming starts, Mae is tied to a post and gagged, and seems to change her mind about killing Julian halfway into the scene. The dummy bullet in the other barrel is discharged and Julian is unharmed, while the director is pleased with the unusual level of conviction in Mae's performance. Meanwhile, the shotgun is borrowed by a props man working on Andy's set, and while swinging from a chandelier Andy is shot with the genuine bullet and plummets to his death. Andy's body is carried past Mae as she films her final scene with Julian, who realises her intention to kill him. Mae screams in shock and faints.

Some time later. Two extras in a film studio canteen read a copy of Picturegoer magazine with Julian on the cover: he is now a leading director. The letters page features a reply to an enquiry about Mae, informing readers that she has not completed a film since My Man. One of the extras professes never to have heard of her. Julian is working in the studio, and asks for an inconspicuous female extra to be found. His assistant wanders through the canteen full of costumed extras, and chooses a simply dressed woman sitting alone. After she is shown where to stand and Julian has directed the scene, the woman is revealed to be Mae. The studio lights are turned off and the technicians pack up, leaving Mae alone on the set with Julian. She asks him if he needs her anymore, to which he shakes his head distractedly, and Mae leaves the studio. Despite a brief flicker of recognition, Julian fails to identify his ex-wife.