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.
Don't you go sneaking girls 
over just because I'm out,
Halt du dich lieber von den Mädels fern, wenn
ich weg bin und unsere Eltern im Urlaub sind.
No vayas tú detrás de chicas
porque yo no esté
No vayas tú detrás de chicas
porque estoy fuera
Et toi, ne profite pas du voyage
de nos parents et de mon absence
Tu, piuttosto, vedi di non portare qui
delle ragazze di nascosto
Cuidado você pra não 
aproveitar que eu estou fora
Это ты не смей
приводить сюда девчонок,