The protagonist of the story, Konoha Inoue, is a seemingly normal senior high 2nd year student. His high school life, other than a hinted incident 2 years ago, can be summed up as normal- if one can dismiss the secret fact that he used to be a female bestselling romance author. Due to that incident, however, he has now vowed never to write again. This continued on until he was forced to join the literary club by the literary club president, the 3rd year female student Amano Tooko, a beautiful girl who has a taste for eating literary works. Now he has been tasked with writing her snack every day after school.

Ranma and the gang are invited to a boating trip with Kuno. Unfortunately, a storm destroys the yacht and everyone is stranded on a remote island. The whole situation goes even more awry when one by one, the girls disappear without a trace. Ranma then finds out that the girls are abducted by Toma, ruler of the island, as part of his personal harem.

In a dark corner of the universe, intergalactic criminal Kain breaks out of prison and destroys the Galaxy Police Headquarters. Basking in the afterglow of the terror and destruction he has caused, Kain sets his sights toward a much bigger prize waiting on Earth. Meanwhile, Tenchi Masaki and his crew are watching some old home videos of his mother, Achika. As the film rolls, Achika slowly starts to vanish. While watching her fade away, Tenchi also begins to disappear. However, thanks to a device created by Washuu Hakubi, Tenchi is not gone for good. The gang soon learns about Kain and deduce that he must have done something to Achika, which has resulted in time being altered. To save himself and maintain the future, Tenchi travels with the girls back in time to protect his mother from her fate.

It's been several years and Kyosuke Kasuga is now 19. A mysterious phone call warns him of oncoming cars but he doesn't listen. Ironically, he gets hit by a car and because of his telepathic abilities, gets sent three years into the future. His 22 year old future self is now a photographer who is lost in Bosnia and believed to be dead. Kyosuke must find his 22 year old future self and restore himself, the 19 year old, to his correct time. Along the way he reunites with Hikaru who is now a professional and famous dancer. Madoka is also there, distraught over both Kyosuke, the 22 year old, going missing in Bosnia and Kyosuke, the 19 year old, getting hit by a car.