The embattled mixed martial arts expert, Eddie Castillo, is released from jail after swearing to never enter the pit fighting ring again. However, after his brother is killed in the ring by a vicious new fighter, Eddie goes on a quest for revenge. His journey takes him through the depths of the underground pit fighting circuit, where he finds people like Lucky, who help him; while others, such as the nefarious Argento will stop at nothing to see Eddie fail.