The demonic space criminal Kain has escaped from prison and destroyed the Galaxy Police headquarters. In a desperate attempt to prevent the Jurai from halting his malevolent plans, Kain travels back in time to 1970 with the intention of eliminating Tenchi's mother before he is even born. Determined to prevent their hero's demise, Tenchi and his friends embark on a perilous journey through time to intercept Kain and alter the course of their own destiny.