Arata Kasuga's life falls apart as a bizarre incident causes worldwide destruction and takes his cousin, Hijiri Kasuga, to another world; Arata enrolls in the Royal Biblia Academy, where the Trinity Seven await.

Pride, Envy, Wrath, Sloth, Greed, Gluttony, Lust. These are the seven sins laid upon seven girls who rule over Biblia Academy. To retake his world, the boy decides he must control these sins... The boy, Arata Kasuga, has had the world he knows by a mysterious "Collapse Phenomenon", and his cousin Hijiri disappears into another dimension. To understand the Collapse Phenomenon and win back his cousin, he comes to Biblia Academy. There he finds the seven girls and their sins.—Crunchyroll