As a new school year starts, both Atsushi and Atsumi face misunderstandings with the new batch of students.

Atsushi's friends try to teach him how to ride a bike without training wheels.

As Atsumi ends up making too many snacks for Atsushi and his friends, she invites over Sayo, who continues to misunderstand who Atsushi really is.

Atsushi, Atsumi and their family go to a hot spring inn where Atsumi's height becomes a bother for her.

Atsumi has to act as Atsushi's parent so he can participate in his school's sports festival.

Atsushi and Atsumi have lunch with Sayo before participating in a relay race.

Sayo learns the truth that Atsushi is Atsumi's little brother.

Atsushi wears some clothes handed down from Take, which prove to be a bit controversial.

Atsushi and his friends go to Atsumi's school culture festival where he runs into Sayo.

Sayo mentions to Atsumi she has always wanted a little sister.

A game of hide and seek soon turns into a frantic escape from the cops for Atsushi.

Atsushi joins Atsumi and Sayo to a family restaurant.