After Jinpachi Mishima was killed,his son,Heihachi took over his place at Mishima Financial Group. He also became King of the Iron Fist Tournament. He tells the competitors that anyone beats him will take home the prize money and fame.
During the Mixed Martial Arts Tournament,Kazuya faces off his opponents.
After he wins,Kazuya notice Heihachi's announcement on TV. He begun practicing while flashing back of being thrown over the cliff as a child. He was later enter along with other competitors,Nina Williams,King,Jack,Marshall Law,Michelle Chang,Paul Phoenix,Yoshimitsu,Bryan Fury,Sergei Dragunov,and Bryce Adams.
The First Round begins. Jack fights with Yoshimitsu and defeats him. Michelle defeats Paul as well. Dragunov and Bryan Fury fought each other. Fury overpowers and kills him. Bryce was about to kill Nina,but gets himself killed.
King fights with Heihachi,who overpowers and kills him. Kazuya fights with Marshall and defeats him. Kazuya begins a flashback where he finds his mother dead.
The Second Round begins,Nina defeats Michelle. Heihachi ripped off Jack's arm,revealing to be an Android created by Doctor Bosconovitch. Heihachi blows a hole in his chest,causing him to shut down. Kazuya fights with Fury,who was about to kill him,but Kazuya wrapped his legs around his neck and kills him.
Before the Semi-Final begins,Kazuya flashes back again. It is revealed that Heihachi is his father and was the one who killed his Mother. After he was thrown over the cliff,He was awoken by a strange gene in him. Later,Williams was forced to shoot Kazuya,which leaves her to fight with Heihachi.
As the Final begins,Three of Heihachi's men were killed by a Flying Demon,who turns out to be Kazuya in his Devil form,due to his gene. Williams kills four of Heihachi's men while Kazuya reveals himself to his father. The two fight eachother and Heihachi receives a beating. Kazuya grabs him by the neck and takes him to the cliff where he drops him. Kazuya change back to his human form and took over his place. He looked at his hands,believing that his mother could have the Gene as well.