Several years have passed since the events of the previous film. Yuri Boyka lives in Kiev, where he trains and fights, with the support of his manager Kirill. Meanwhile, in Russia’s Black Hills Prison, where Yuri was once the undisputed champion, a new champion has emerged – an insane convict nicknamed “Nightmare.” During a qualifying match, the winner of which will be able to participate in the international European MMA Championship in Budapest, Boyka accidentally kills his opponent, Russian fighter Viktor Gregov. Tormented by guilt, he decides to meet his widow, for which he decides to go to Russia, which can end quite badly for him, given that he is a fugitive.
Using a fake passport, Yuri safely gets to the city of Drovny, where he finds the widow of a soldier, Alma, working with children in a kindergarten. It turns out that Victor and Alma were financially dependent on the local crime boss Zurab, who now, knowing that her husband is dead, makes her pay the debt, considering her his property. Yuri visits the Vulkan club, where Alma works at night as a waitress and finds that no one is allowed to see her, having a rude conversation with Zurab himself in the end. Maintaining an underground arena in the Vulkan club, where Igor Kozemir, the underground champion, wins victory after victory, claiming that this is his ring, Zurab is looking for a dangerous opponent who can put on a grand performance, while Yuri Boyka comes and offers him deal: he will hold three fights for him in the ring, after which Alma will receive complete freedom. Zurab agrees, but reserves the right to change the rules of the agreement. Hereinafter you can watch short scene from Undisputed 4
