Tenchi must travel back in time to the year 1970 to save his girlfriend from disappearing. Along the way, he encounters demons, supernatural powers, and a mysterious Tokyo Tower.

In Tenchi Forever!, Tenchi returns to Earth to find that Ryouko and Ayeka are missing and that the memory of their existence has been wiped from everyone's mind. As he searches for answers, Tenchi discovers a mysterious girl named Haruna who claims to be his wife from the future. With the help of his friends, Tenchi must unravel the truth and save his loved ones.

Tenchi's peaceful life is turned upside down when an ancient evil awakens, threatening his loved ones and forcing him to confront his own inner darkness. With humor and violence, he must navigate rivalries, secrets, and a princess in order to save the day.