Gorō Hanada, the Japanese underworld’s third-ranked hitman, is portrayed by Jō Shishido. He arrives in Tokyo with his wife Mami Hanada, who is played by Mariko Ogawa. They are greeted by Kasuga, a former hitman turned taxi driver, portrayed by Hiroshi Minami. The trio heads to a club owned by yakuza boss Michihiko Yabuhara, where the atmosphere is tense and every gesture seems loaded with danger.
Yabuhara hires Hanada and Kasuga to escort a client from Sagami Beach to Nagano. After the meeting, Yabuhara seduces Mami, pulling her into a dangerous web where loyalties blur and mortal risk becomes routine. As they drive the client toward his destination, Hanada spots an ambush and fires, dispatching several gunmen. In the ensuing chaos, Kasuga attacks Koh, the fourth-ranked hitman, Atsushi Yamatoya, and both men die. Hanada abandons the client briefly to secure Koh’s car, but more assassins close in; after another ambush, he shoots more gunmen, sets Sakura, the second-ranked hitman, on fire, and the client shoots Sakura dead. A broken-down car forces an unplanned stop, and Misako, a mysterious woman with a death wish, offers him a ride.
Misako Nakajô, played by Annu Mari, soon pushes Hanada into a near-impossible contract to kill a foreigner. Amid the mission, a butterfly lands on the barrel of his rifle, causing a miss that results in the death of a bystander. Misako warns that Hanada will lose his rank and be killed, signaling the beginning of a deadly bargaining game. Preparing to leave Japan, Hanada is shot by Mami; she sets their apartment on fire and flees. Hanada escapes, his belt buckle catching the bullet and sparing his life, a small mercy amid chaos.
Reunited, Hanada and Misako cycle between failed seduction and near-kill orders, until Misako yields to his advances when he promises to kill her. He soon realizes he loves her, leaving him emotionally tangled and wandering the streets in confusion. The next day, he finds Mami at Yabuhara’s club. She tries to seduce him again, then fakes hysteria and claims Yabuhara paid her to kill him, revealing that the three men he killed had stolen from Yabuhara’s diamond-smuggling operation and that the “foreigner” was an investigator. Unmoved, Hanada kills her, drinks himself into forgetfulness, and waits for Yabuhara to return, only to find Yabuhara dead with a bullet through his forehead.
Hanada returns to Misako’s apartment, where a projected film shows her bound and tortured, and she directs him to a breakwater where he will be killed the following day. He submits to the plan, but retaliates by killing the assassins instead. The former client arrives, revealing himself as the legendary Number One Killer, and he intends to kill Hanada but grants him a temporary truce as a gesture of thanks for his work. The two men endure a tense truce, Number One moving into the apartment under the pretense that he is weighing how to kill Hanada; they establish routines—when to eat, sleep, and even walk arm in arm in public.
Number One finally suggests they eat out together, then disappears. At Misako’s apartment, Hanada finds a note and another film from Number One, directing him to a gymnasium where the final confrontation will unfold. Hanada goes to the gym, but Number One does not show. In the boxing ring, Number One appears and fires, but the headband Hanada wears absorbs the shot, allowing him to return fire. Number One is able to shoot Hanada several times before dying, and Hanada, triumphantly declaring himself Number One, is interrupted by Misako’s entrance. He instinctively shoots Misako dead, proclaims himself Number One once more, and then falls from the ring, a man who has killed his way to an empty crown.
