The King of Iron Fist tournament returns! Set two years after the events of Tekken 3, Heihachi is trying to splice DNA from True Ogre into his own genome. It doesn't work, though -- he's missing the "Devil Gene" required to complete the task successfully. Of course, he knows just who has it -- Jin! However, things are complicated by the apparent resurrection of Heihachi's murdered son, Kazuya. Amidst this background of turmoil and intrigue, the new tournament begins.