Itsuki Hashima, a popular young novelist whose work always includes little sisters, is having difficulty coming up with a new series. One day, his younger step-brother Chihiro and some of his colleagues come over for dinner, drinks, and games.

Nayuta and Miyako walk in on Itsuki naked!? He's trying to act out the little sister character in his new volume, but he ends up embarrassing himself and complicating the trio's relationship.

Itsuki, Nayuta, and Miyako decide to escape the cold by going to Okinawa where they visit a remote island so Itsuki can do some research. Meanwhile, Nayuta decides to flail around naked in the water, and Miyako eventually joins in as well.

Nayuta, Miyako and Haruto gather at Itsuki’s room for Valentine’s Day, and Haruto tries to show off his friendship with Itsuki again. Toki then shows up with the chocolates that fans had sent to them.

Itsuki is nearing an important deadline and tries to flee from his editor, Toki, but is immediately caught. However, he manages to escape and goes to a hot springs with Setsuna.

Itsuki has a meeting with Kaiko Mikuniyama, the artist who will be doing the manga version of "Mahou Academy." She looks very refined, which makes Itsuki nervous, but apparently she loves little sisters as much as he does.