Super RIZIN

Picking up after the events of Never Back Down 2, former MMA champion Case Walker is on the comeback trail to become champion once again.

A businessman, Tsuda, runs into a childhood friend, Kojima, on the subway. Kojima is working as a semiprofessional boxer. Tsuda soon begins to suspect that Kojima might be having an affair with his fiancée Hizuru. After an altercation, Tsuda begins training rigorously himself, leading to an extremely bloody, violent confrontation.

Nick and Ruben are hoodwinked into a "shootfighter" (no-holds-barred, to the death) martial arts match by the evil Mr. Lee, who has a grudge against world shootfighter champ(and teacher of Nick and Ruben) Shingo.

A former fighter reluctantly returns to the life she abandoned in order to help her sister survive the sadistic world of illegal fighting and the maniac who runs it.