Jim picks up his briefing from a rooftop storage locker on Emil Skarbeck and Kurt Lo, rivals for the chief of secret police of the East European Peoples Republic. The IMF must eliminate both of them and make sure that Paul Trock gets the position, as he is friendly to the West.
In the briefing, Cinnamon and Rollin have prepared the act to that performed by Carlotta Kleve, Skarbeck's girlfriend from years ago who he murdered. They have a letter from Starbeck's psychiatrist, who treated him for mental illness after he murdered Carlotta. Cinnamon tests a drugged ring that puts the victim into a hypnotic state. Jim warns that Skarbeck is emotionally unstable, but they'll use it to their advantage.
At a café in the Peoples Republic, Skarbeck and Trock go to a café where Rollin and Cinnamon are performing, and Trock vouches for Skarbeck. Lom arrives and sits with them, and he and Skarbeck exchange barbs. A masked white-face Rollin appears as the cabaret master of ceremonies, while Jim sits in the audience. Rollin then plays the piano for Cinnamon, who resembles the murdered Carlotta and performs the same act.
Barney sneaks into Skarbeck's house and substitutes IMF pills for Skarbeck's then puts a transmitter in the lid so they know when Skarbeck opens it. After Cinnamon is done, Jim bumps into Skarbeck and says he knows of him, despite the fact Skarbeck keeps a low profile. After Jim leaves, Trock notes that they never did solve Carlotta's murder. Cinnamon sends a note to Skarbeck asking to meet him. Skarbeck says that Fritz Mueller, Carlotta's co-star, was the murderer but he died in a car crash. After Skarbeck leaves, Lom says that he knows Skarbeck murdered Carlotta.
Skarbeck finds Jim meeting with Cinnamon. After Jim leaves, Cinnamon says she was a friend of Carlotta and copied her act. Skarbeck says she's lying and Cinnamon admits Lom paid her to seduce him for an unstated reason, and she worked out the act from old films. She agrees to meet with him at his house in an hour.
Jim meets with Lom and has evidence concerning the Carlotta murder case. Jim introduces himself as the brother of psychiatrist Becker that Skarbeck killed to cover up his blackout and mental collapse after the murder.
Skarbeck meets with Cinnamon and vows not to love any woman again. Skarbeck gives her a miniature tape recorder to record Lom when he gives her further instructions. She prepares to leave but they kiss. Meanwhile, Jim suggests to Lom that they instigate an emotional collapse in Skarbeck by getting her obsessed with Cinnamon. He suggests that Lom "persuade" Cinnamon to cooperate then leaves, and Lom considers tricking Skarbeck into killing Cinnamon and arresting her for that murder.
Cinnamon and Skarbeck are on her couch when she signals Rollin, who bursts in to "protect" her and take her back to the hotel. Cinnamon leaves with Rollin while Barney and Jim listen in and determine he's taking a pill. They break into the house as Skarbeck collapses. En route to the hotel, Cinnamon is picked up by the police and taken to Lom who finds the tape recorder.
Jim interrogates the hypnotized Skarbeck who describes how he met with Carlotta and then killed her in a jealous rage. Meanwhile, Lom pays Cinnamon to lure Skarbeck to the café and drive him into a rage. After she leaves, Lom tells his assistant Otto to make sure Cinnamon dies. Jim tells the hypnotized Skarbeck to love Cinnamon the same way he loved Carlotta.
Later at the café, Cinnamon performs as Skarbeck watches her. Afterward Skarbeck goes backstage and goes into her dressing room, but finds another man's coat. Rollin turns on a tape player in his dressing room of him and Cinnamon laughing and Skarbeck hears it and barges in. Rollin denies Cinnamon was present or that they were together, and takes off his sunglasses to show his eye was disfigured in a car accident and that he was Fritz Mueller, who supposedly died in the car crash. Rollin says he was never Carlotta's lover, but that she and Lom were together. He then found Cinnamon and trained her in Carlotta's act, but Cinnamon has no use for him either.
Cinnamon goes to Lom and asks for the money but he says she'll have to wait 48 hours. Once she leaves, Lom tells Otto to follow and killer her when he gets the chance. Outside Skarbeck confronts her and Cinnamon claims she went to Lom to tape his instructions as Skarbeck asked. She takes him back to his house while Jim, Barney, and Rollin go to Trock and has him arrange a meeting with Lom at the café. Jim warns Trock to wait until the blackout to act.
Skarbeck demands to see Cinnamon's initial payment and she shows him the tape. There's nothing on the recorder and Cinnamon claims the machine is malfunctioning. Skarbeck believes Cinnamon betrayed him with Lom, and Cinnamon humiliates him. Skarbeck starts to strangle her and she drugs him with the ring. Willy then arrives as Otto looks on from outside. Willy takes the dazed Skarbeck away and then Otto prepares to shoot Cinnamon but Jim knocks him out.
Skarbeck wakes up at the café and "Rollin" wakes him up, while Willy plays Rollin's voice over his suit lapel. Cinnamon doesn't come out so "Rollin" goes backstage. Jim and Lom arrive and accuse Skarbeck of having killed Cinnamon. However, Trock comes in with Lom as well. Skarbeck goes for his gun and Willy shuts down the lights, then turns them back up. The real Lom is standing is approaching him and Skarbeck shoots him. The first "Lom" reveals he was Rollin in disguise, and that the "Rollin" on stage was Barney in makeup. The entire team slips outside and makes their escape.