Two years after the events of the King of the Iron Fist Tournament, the Mishima Zaibatsu, under the leadership of Kazuya Mishima, has become even more corrupt and powerful than ever before and involved in many illegal operations. These include kidnapping, extortion and smuggling endangered animal species for illegal experiments. Kazuya is backed by the Devil, which inhabits his body and is trying to take over his mind. Meanwhile, animal rights activist and operative Jun Kazama is sent to arrest Kazuya for his experiments.
Kazuya's father, Heihachi, whom Kazuya had defeated and thrown off a cliff after the previous tournament, has climbed back up and is training himself, plotting to overthrow Kazuya. In an attempt to rid himself of Heihachi and his enemies once and for all, Kazuya announces the King of the Iron Fist Tournament 2, with a large cash prize of one trillion dollars, knowing that Heihachi would appear.
Jun Kazama eventually comes face to face with Kazuya, but rather than arresting him, she finds herself drawn to him. She later became pregnant, with Kazuya having fathered her child. Meanwhile, Heihachi arrives at the tournament, winning against the opposing fighters and eventually reaching Kazuya.
In the final round, Heihachi confronts Kazuya and they battle once again. Devil takes over Kazuya's body, resulting in Kazuya becoming a Devil creature. Despite his advantages, Kazuya is defeated by Heihachi because of the internal conflict within him (between his evil side - represented by Devil - and his good side - represented by Angel - which was brought forth after his meeting with Jun Kazama). Heihachi then takes Kazuya's body to a volcano, and drops him into it to kill him. Heihachi then escapes on a helicopter as the volcano erupts behind him, having finally taken his revenge and regaining the Mishima Zaibatsu back, with Kazuya presumably dead.