Chan, an articulate senior detective nearing the end of his career, is taking care of the daughter of a witness killed by ruthless crime lord Po. Martial arts expert Ma is set to take over as head of the crime unit, replacing Chan who wants an early retirement.

A Hong Kong cop named Kit busts a major gangster only to find his cover blown and his main witness gone. The gangster, in retaliation, has him kidnapped and put in a Thai jail with a false criminal identity. Lowly prison guard Chai, with his extraordinary fighting skills, guards Kit and prevents his escape. The prison guard’s daughter suffers from a rare form of leukemia and Kit is the only donor who can save her. The prison guard discovers Kit’s real identity and helps him to escape in return for his agreeing to save his daughter. Together, Kit and Chai must face and take down the gangster and his minions.

When a Hong Kong police negotiator is informed about the sudden disappearance of his 16-year-old daughter in Thailand, he travels there to search for her whereabouts.