The girls are running in their exercise outfits, with the boobs swaying to and fro. Arata's heart races. Everyone's having great time, and then a ghost appears in the library. Arata and the gang go to check it out, and are forcefully transported to the "Eternal Library". There they find the lost Trinity Seven!

Lugh attacks the school while Arata and Mira are being held far away. Yui evacuates everyone in the school into her dream to protect them, and Levi sets out to fight alone. But Lugh is a demon lord candidate who has obtained a demon lord element.