Itsuki Hashima is a popular, young novelist. However, he is obsessed with little sisters and his works seem to always include little sisters, so there’s some difficulty coming up with a new series. One day, his younger step-brother Chihiro and his colleagues, Hayato Fuwa, Nayuta Kani, and fellow college student, Miyako Shirakawa show up at his apartment. They enjoy dinner, drinks, and a game. That night, Nayuta makes advances towards Itsuki, but...
What? But our hot night 
together is just starting.
Waaas? Unsere heiße
Nacht beginnt doch erst!
Pero nuestra gran noche
acaba de empezar.
Pero nuestra gran noche
acaba de empezar.
Eh? Ma la nostra notte
di passione è appena iniziata!
O quê? Mas a nossa noite
 só está começando.