Dong Sik leaves behind a fist-covered past and heads down to Busan, where his beloved Yeon Hee awaits. However, his beloved Yeon Hee has already become someone else's wife and her whereabouts are unknown. Dong Sik plunges back into the dark underworld. He receives a murder contract from the smuggling boss, Baek Han Seong. Around that time, a stranger who arrived by night train becomes Baek Han Seong's subordinate. Meanwhile, Dong Sik discovers that Baek Han Seong's wife is indeed Yeon Hee. He infiltrates Baek's lair and unleashes his vengeful fists. Just then, the man who arrived by night train helps Dong Sik and cooperates in crushing his gang. It turns out he was an investigator.