After masked attackers kill her sister and young nephew, a female psychologist takes the law into her own hands by acting as a defense witness by day and a ruthless avenger by night.

Thomas Hoshino is a tough Japanese detective, who lost his partner by a deadly Yakuza killer Jaho. He tracks down the killer and his master to Los Angeles, where he teams up with Det. Karen Ryder. Soon they discover that Jaho is preparing a gang war and weapon smuggling ring. Hoshino must find a way to defeat the killer who posses mystical ninja powers.