As his family takes off for a few days, Seiji finds himself home alone. Well, except for Guri, of course. But the peace of the moment is short-lived when Akane shows up at his door saying she's there to spend the night while his family is away and to claim the kiss that Seiji had promised her. Things only get more complicated as usual when Yuzu and Shikimi show up as well. Things seem to go rather okay until Seiji's younger sister Akua returns home early to find Seiji surrounded by all four girls in a compromising situation and proceeds to scold her brother for his behavior. Curious about the siblings' relationship, Guri drags Akua out shopping to get to the bottom of her brother-complex.
Jeez! When you think of a bath scene,
you usually expect to see a girl's bare skin.
Oh Mann,
Cuando imaginas una escena en un baño,
esperas ver a una chica desnuda.
Cuando imaginas una escena en un baño,
esperas ver a una chica desnuda.
Bon sang…
Ma insomma! Quando si pensa alla scena del bagno,
ci si aspetta di vedere il corpo di una ragazza.
Puxa! Quando se pensa numa cena de banho,
 a imagem que vem à mente é de uma menina!
Эх! Когда представляешь сцену в ванной, 
то думаешь, что увидишь там девушку.