Fifteen years after the King of the Iron Fist Tournament 2, Heihachi Mishima has established the Tekken Force, a paramilitary organization dedicated to the protection of the Mishima Zaibatsu. A squadron of the Tekken Force searches an ancient temple located in Mexico. Soon after arriving there, Heihachi learns that they have been obliterated by Ogre. However, Heihachi, having witnessed the event, seeks to capture Ogre in hopes of harnessing its power for his own gain. Soon after, various martial artists end up dead, attacked or missing from all over the world, with Ogre behind it.
Jun Kazama has been living a quiet life in Yakushima with her young son, Jin, fathered after the events of the previous tournament by Heihachi's son, Kazuya. However, their peaceful life is disrupted when Jun begins to feel the encroaching presence of Ogre. Jun is now a target and instructs Jin to seek Heihachi should anything happen. Sometime after Jin's fifteenth birthday, Ogre indeed attacks. Against Jun's wishes, Jin valiantly tries to fight Ogre off, but Ogre knocks him unconscious. When Jin awakens, he finds that his house has been burned to the ground, and that his mother is missing and most likely dead. Driven by revenge, Jin is confronted by the Devil, which brands Jin's left arm and possesses him. Jin goes to Heihachi, explaining his situation and identity and begging him for training to become strong enough to face Ogre. Heihachi accepts and takes Jin in, as well as sending him to school.
Four years later, Jin masters the Mishima karate style. On Jin's nineteenth birthday, Heihachi announces the King of the Iron Fist Tournament 3, secretly intending to lure out Ogre, while Jin prepares for his upcoming battle.
In the tournament, at a large temple, Paul Phoenix defeats Ogre and walks away from the tournament, thinking he is victorious. However, Ogre transforms into its true form of a monstrous beast, and Jin finally confronts it. Jin battles and defeats Ogre, and the being completely dissolves. However, Jin is suddenly gunned down by a squadron of Tekken Forces led by Heihachi, who, no longer needing him, personally fires a final shot into his grandson's head.
However, Jin, revived by the Devil within him, reawakens and dispatches the soldiers, smashing Heihachi through the wall of the temple. Heihachi survives the long fall, looking up to see Jin sprout feathery wings and fly off into the night.