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...
but unfortunately in this world,
Aber in dieser Welt ist es
nun einmal leider so,
pero, por desgracia, ser bueno y correcto no 
basta para ganarte al resto en este mundo.
pero por desgracia, ser bueno y correcto no 
basta para ganarte al resto en este mundo.
Mais malheureusement, 
en ce bas monde,
ma in questo mondo, sfortunatamente,
mas infelizmente neste mundo,
Но в этом мире, к сожалению, чтобы понравиться 
недостаточно быть честным и справедливым.