Amateur Vigilante summary: Action thriller about an obsessed lonely man with a delusional plot to save Japan by assassinating a politician. But his twisted plan is disturbed when he witnesses a young girl next door getting abducted by the Yakuza. He decides to save her but his attempt ends in a chaotic massacre where he manages to kill the gangsters. But things only get worse from here on out, now he's getting hunted down by even more ruthless killers.