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...
Since Mio and I both became 
bitches and submitted to Basara,
Da Mio und ich uns Basara
als Hündinnen unterworfen haben,
Desde que Mio y yo nos 
dejamos someter por Basara,
Desde que Mio y yo nos 
dejamos someter por Basara,
En devenant des chiennes
Da quando io e Mio ci siamo sottomesse 
al nostro padrone Basara
Desde que eu e a Mio decidimos
 nos entregar ao Basara,
Из-за того, что мы с Мио стали собачками 
и подчинились Басаре,