A man with no recollection of his past wakes up in an apartment in a district outside Tekken City before he is chased by armed men and nabbed by a female assassin named Rhona Anders. He is brought to a guerrilla leader known as “The Minister”, who gives him the letter “K” as his codename and has an explosive surgically implanted in his chest, should he fail his mission or attempt to leave the organization. Despite his amnesia, “K” displays exceptional skills in fighting and marksmanship. He befriends the district’s local janitor, whose son killed his wife and crippled him before disappearing three years prior. After defeating an opponent in a sparring match, “K” is ordered by the Minister to kill him or the janitor; “K” declines and tells the Minister to let the janitor go, to which the Minister’s henchman breaks the defeated opponent’s neck.
Over the next few days, “K” is given an apartment unit where he plots his next targets. He befriends a tenant named Laura after saving her from a couple of muggers. After one of his jobs, he tells Rhona he wants out. Recalling the events from where he first woke up, “K” returns to the apartment building from the beginning of the film and asks the manager for records on his previous stay, to which the manager only has him signed under the initials “K. M.” On his next job, “K” battles and is defeated by his target, Bryan Fury, who warns him to walk away from his job before disappearing. The next morning, “K” confronts Rhona about Fury, who is revealed to be a former associate of the Minister. As Laura is a nurse, “K” has her remove the explosive from his chest.
“K” receives a call from Fury, who warns him that the Minister has “K” marked as a target. He meets up with Rhona that night before they both encounter Fury, who shows them a newspaper article and tells them they are all pawns of the Minister. Later, Rhona stabs the Minister in the back, but “K” later on discovers that Laura has been abducted by Gentek Factory. The duo sneak into Gentek, where Rhona battles and defeats the Minister’s female assassins. “K” meets Heihachi Mishima, who reveals that “K” is his son Kazuya Mishima. Like the ancient Spartans sending their male children to the wilderness to survive alone, Heihachi had Kazuya brainwashed and set loose to test his survival skills. Heihachi shows Laura who has been brainwashed also. The brainwashing process has changed her from calm and sweet girl into seductive hot lady. Kazuya’s body is filled with rage when Heihachi kills Laura after they are kissing each other. Kazuya then battles two fighters named Rip and Thorn. After defeating the two combatants, Kazuya accepts his bloodline and has Rhona accompany him to find Heihachi, who stands over the skyline of Tekken City.