A young boy by the name Habiki Yorgana is summoned into another world alongside his classmates, during their field trip from school. After their summoning they’re surrounded by many life threatening dangers, however they’re soon told by the summoners themselves that they were summoned here for an specific purpose.

In order for them to return back home, they must eliminate an evil corruption that spreads through their lands, and destroy them. The summoners calls them Vanquishers, and these Vanquishers are summoned once every 5,000 years to eliminate this mysterious evil that keeps coming back.

Habiki takes advantage of this from being an Otaku in the heart, and thus he has the most advantage over everyone else. He watched many Isekai animes and read hundreds of Mangas to know what to do, and what not to do… however he ends up finding out that he has the most broken system in this world, leaving him shocked.