Hanaoka high school is an all girls' school, and the girls were pretty excited when they heard that boys were admitted into their high school. Smart and elegant boys, that's in their fantasy. However, in reality, the boys who were actually admitted are from the countryside and not smart at all, leave alone being elegant. And in fact, two of them are dirty perverts...

Episode 0 of Seikaisuru Kado premiering on Amazon Prime.

After an embarrassing high school class reunion with their successful classmates, who have "proper" jobs, relationships, and even children, the Matsuno sextuplets return home to sulk about their status as NEETs. They spend the night drinking away their sorrows, eventually falling unconscious, until they awaken in a strange world of memories, centered around one of the brothers' biggest high school regret.

As the sextuplets navigate this memory world, they encounter their embarrassing past selves from high school, as well as those of their friends. All the while, they try to uncover whose regret was great enough to trap them in this strange world, so that they can make their way back to reality. However, they're running out of time; this world of memories is unstable, and the sextuplets may lose their chance to make things right if they're too slow....

Genki is a boy who loves playing video games. One day he's zapped into the world of Monster Rancher and meets the girl Holly and the monsters Mochi, Suezo, Golem, Tiger and Hare. Continuing from where the original story left off, Genki and friends journey to conquer the legend cup in hopes of freeing Holly's father from the mystery disc. (Source: AniDB)