Fujiko is sitting in a casino, winning at roulette thanks to her earring. The casino owner approaches and makes her an offer: the casino for Fujiko herself. Despite her earring, Fujiko loses. The casino owner has Fujiko brought to a bedroom and stripped. She says Fujiko can be released if she does two things: steal a gun from a man and "see it through to the end."
A Mr. Exposition
explains that the owner, Cicciolina, inherited the Italian Family after her husband, the previous boss, was killed by Jigen Diasuke, whose gun Fujiko is supposed to steal. Jigen then defected to rival gang, the Chinese Family, who has since taken over. Cicciolina says Jigen's weakness is women.
Fujiko wins the audition for the Chinese Family's new lover. Upon meeting Jigen, however, he is cold and says it is not the duty of bodyguards to protect women. Over time, Fujiko tries to charm Jigen, though he catches her with a knife, which she claims she had for self-defense. Eventually, Jigen opens up and says a bodyguard must be suspicious of everyone.
He relates his past: during the interview with the head of the Italian Family, he impresses both the boss and his wife. Later, he finds Cicciolina collapsed on the floor after trying to take her own life. He sends for a doctor but she asks to let her die. She awakes in bed with him watching over her. In answer to her question, he says a man must retain some compassion and a women must retain some hope, and so he didn't let her die because she didn't really want to. Later, the boss admits he doesn't know what to do with her, as this is not the first time she attempted suicide, but asks Jigen to watch over her. One night, Cicciolina asks the boss if she can have Jigen for the day. At a club, he refuses to dance with her then does in order to be inconspicuous while keeping her close, killing a suspicious couple when they draw pistols.
Fujiko snaps him out of his reminisces with a kiss, which is drugged. While he is addled, she steals his .357 Magnum and leaves a message: she will be waiting where they made love. Fujiko brings the gun to Cicciolina, who again requests that Fujiko see it through to the end. In another flashback, Jigen remembers the church where he found Cicciolina lying in a coffin. However, she is only playing dead, and when the boss shouts for her, she pulls Jigen into the coffin and closes the lid, where she seduces him. Later the boss, who is suspicious, says he'll kill Jigen. Cicciolina grabs him and, in the struggle, the boss is shot. Jigen arrives and says their story will be that he shot the boss and that she had nothing to do with it, and he beats a hasty escape.
Jigen arrives at the church. Cicciolina says she used him to grab power. Now she is with someone else and intends to kill the only witness to her crime. Jigen deals with her mooks, but Cicciolina says he won't shoot her, drawing his Magnum. He shoots, only to find she hadn't loaded the gun. She confesses that she became empty after he left, and if she was to die, she wanted him to kill her. At the cemetary, Fujiko remarks that she saw herself in Cicciolina but won't let her past her kill her as she will always outrun it. Jigen says he's giving up being a bodyguard; if you hesitate, you die, and so you can't feel any emotion. He think maybe he'll try the carefree life of a thief instead.
.357 Magnum provides examples of:
- Bodyguard Crush: Jigen is ordered to protect Cicciolina by his boss, despite Jigen's attempts at refusal, because the boss wants his wife protected. Cicciolina develops a crush on Jigen, and manipulates him into awkward situations such as having sex in a casket.
- Even the Girls Want Her: Cicciolina is about to declare that all men would find Fujiko fascinatingly beautiful, when she corrects herself and says that Fujiko attracts even the women.
- Film Noir: This episode contains many characteristics of this genre.
- Spurned Into Suicide: Cicciolina can't live without Jigen, even though he left her so she wouldn't get killed.
- Suicide by Cop: Cicciolina set up the events of the episode (excluding the flashbacks) to manipulate Jigen one more time. She brought her goons there to shoot at him, knowing he was a better shot. She got her men killed by him and aimed Jigen's Magnum at him, manipulating him so that she could die by his hand.
- William Telling: The Italian Mafia boss has Jigen shoot a cherry from between Cicciolina's lips to demonstrate his skill as a gunslinger.