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.
They all just snuck in 
where I was sleeping!
Die sind alle von sich aus
zum Übernachten gekommen!
¡Todas llegaron
cuando ya estaba durmiendo!
¡Todas llegaron
cuando ya estaba durmiendo!
Elles sont toutes venues
durant mon sommeil…
Sono venute qui 
tutte di nascosto mentre dormivo!
Elas se enfiaram onde eu estava dormindo!
Они все пробрались ко мне, пока я спал!