In the fourth installment of the fighting franchise, Boyka is shooting for the big leagues when an accidental death in the ring makes him question everything he stands for. When he finds out the wife of the man he accidentally killed is in trouble, Boyka offers to fight in a series of impossible battles to free her from a life of servitude
Deep in the Mariana Sea Trench, a corporate underwater mining complex has been built – an industrial Atlantis. When an accident in a dry-dock chamber kills several miners an investigator is sent to find the cause and immediately finds out that it was not an accident. He becomes caught in the middle of a deadly conflict between the miners and the corporation, and fights to stay alive and uncover the truth.