After ending the battle against Zolgia, Basara regains his peaceful life with his two little sisters, Mio, the daughter of the previous demon lord, and Maria, her little sister who's also a succubus. As Basara pursues the preparations for the sports festival at school, one day he's attacked by a person being manipulated by magic. Recalling the strange gaze he felt at school, a suspicion of his begins to grow...
Why did you make Kurumi go 
that far when we haven't
Warum hast du es mit
Kurumi so weit getrieben,
¿Por qué hiciste que Kurumi llegara a tales
 extremos sin haber formado un pacto?
¿Por qué hiciste que Kurumi llegara a tales 
extremos a pesar de no haber formado un pacto?
Kurumi n’a pas conclu 
de pacte d’allégeance avec moi,
Perché mettere Kurumi in una situazione 
del genere quando non siamo neanche legati
Por que você fez tudo aquilo
 com a Kurumi sendo que nós
К чему так далеко заходить, если я
 с Куруми и контракта не заключал?