Woo-sol is a young victim of bullying and loses his freedom when he fights back and seriously wounds his juvenile aggressor, Seok-chan. Woo-sol is sentenced to a juvenile detention center where he meets Do-hyun, a mixed martial arts champion, and convinces him to teach him to fight. With the champ's help, Woo-sol overcomes his physical and mental limistations in preparation for the inevitable and unavoidable rematch with his former bully who vowed to kill him upon his release from detention. Through strict, painful training, Woo-sol awakens the killer shark instinct within himself and prepares for his approaching release