Dan goes to a theater and is briefed on the fact that two espionage groups in an enemy country are vying to assassinate a defector, Napolsky. The U.S. wants the older group to succeed so the IMF must discredit the head assassin of the younger group, Andrei Fetyukov, so that the group led by Colonel Shtemenko can take control.
Dan selects Barney and Cinnamon for the mission and Cinnamon goes over Fetyukov's fan. Dan warns that Fetyukov is ruthless and shouldn't be underestimated, and Cinnamon is intrigued. Dan and Barney will be dealing with Shtemenko, and acting as bait for Fetyukov.
Dan and Cinnamon arrive at a reception for the scientific conference where Fetyukov notices Cinnamon and dances with her, while Dan watches and Barney listens in. Fetyukov returns her to Dan then heads for the library when he spots Shtemenko heading for the library. Meanwhile Barney meets with Napolsky and lets him help wire photoelectric equipment.
Fetyukov and Shtemenko argue over who should handle Napolsky's assassination while their government official, Suverin, mediates. Cinnamon comes in and tells Fetyukov she's leaving and would like him to take her home, and indicates that she has a cigarette with a transmitter in it. Suverin dismisses Shtemenko and assigns Fetyukov to the mission. Fetyukov wonders why Cinnamon is so obvious but admits it will be fun to find out. He goes to get Cinnamon, who destroys the cigarette transmitter. Meanwhile, Dan lets slip that he knows who Shtemenko really is. Later he slips into Napolsky's room with a gun but sets off a photoelectric light barrage catching Dan's attack on film. Dan assures Napolsky that they plant to make Shtemenko look as bad as possible by capturing him on film. He then makes a false phone call to Shtemenko to make him suspicious.
Fetyukov and Cinnamon meet for a series of dates over the next several days while sparring over each others' secrets and to hint to each other they might defect. They end up in Fetyukov's hotel room, while Shtemenko listens in and later plays the recording to Suverin. He claims that Fetyukov plans to defect and has pointed him out to the Americans. Meanwhile Dan points out to Cinnamon that Shtemenko has been following her but Cinnamon wasn't aware of it. Dan plans to make his move that night and wonders if Cinnamon is getting caught up in her own performance.
That night they are on the balcony of Fetyukov's room and he spots Shtemenko watching them, while Dan watches Shtemenko. He then approaches the colonel and offers to kill Napolsky for him. He explains that Shtemenko won't be involved and no trap is involved. The colonel is suspicious but Dan says he wants out once he's completed the kill and is paid $50,000. Shtemenko tries to bargain but Dan only says he'll meet to collect the next night.
Suverin gets Shtemenko $22,000 and provides a list of the guests. Fetyukov arrives and they tell him that Shtemenko is retiring. Once he leaves, Suverin demands an explanation and wonders what Fetyukov has been doing for five days. Shtemenko goes to Dan with the money but he refuses to take less. As he gets up to leave, he bumps into Barney who says his "real" name. Shtemenko takes the bait and looks up Dan's hotel room on the guest list, then goes there and breaks into the room next door then slips in to Napolsky's room. The flash cameras go off and Dan and Barney grab him, then explain they can ruin Shtemenko but won't if he leaves the country with the money. He hastily pretends to take their offer, exactly as planned.
Shtemenko burst in on Fetyukov and Cinnamon and accuses him of tyrant to blackmail him. Cinnamon distracts him long enough for Fetyukov to disarm him and throw him out. Fetyukov concludes Cinnamon's mission was to set him up for Shtemenko but now she's switched sides and he assumes she's fallen in love with him and they end up in bed.
Dan gets word that Shtemenko died of a "heart attack" and they're both concerned about Cinnamon. The next morning Fetyukov suggests that he wants to defect but Cinnamon pretends she doesn't believe him. He notes he has no one his superiors can use as a hostage against him, and even admits he might love her, except she's too cynical to believe him. As he prepares to leave, Cinnamon warns him away from the conference and he prepares to find asylum elsewhere. Convinced, she goes to see Dan, unaware that Fetyukov is following her.
Cinnamon arrives at the hotel room but Fetyukov arrives and holds them all at gunpoint. Napolsky comes out and Fetyukov prepares to shoot him, but Cinnamon advances on him and when he shoots her, he realizes the gun is unloaded: Cinnamon unloaded it the previous night. She slaps him and they get photos of Fetyukov's humiliation. They toss him out and Napolsky offers his thanks. Dan figures that Cinnamon knew Fetyukov was going to follow her and he congratulates her on being a talented liar. He apologizes for doubting her and leaves, and Cinnamon is left alone.