It's time for the school cultural festival! Excitement is in the air as life seems to be back to normal for Seiji, Akane, and the rest, but all is not what it seems. Shikimi suddenly has transferred into Seiji's class and it now has Akane on edge. When its decided that their class will be putting on a play with Shikimi in the leading role of the princess Akane is roped into playing the prince while Guri gets to play the rival pirate to the prince. On top of all this even Yuzu has started acting strangely and Seiji finds himself stuck in the middle, as always.
I absolutely will not allow you 
to be alone with Onee-sama!
Schwesterherz mit Seiji
unter einem Dach
¡No te dejaré a solas con mi hermana!
¡No te dejaré a solas con mi hermana!
Non posso permetterti
di stare da solo con Oneesama!
Eu jamais permitirei que você 
fique sozinho com a minha irmã!
Ну а как иначе?!