A kotatsu (heated table) was set up in the Kouda family's living room. Kujima, completely captivated by it, spent most of his days under the kotatsu and ended up getting quite plump. Meanwhile, Arata, who had been playing around instead of studying since Kujima arrived, finally got his comeuppance on his final exams, scoring only 38 points. He decided to invite Makoto over for a study session.

Shin realizes he's forgotten his winter break homework in the classroom, so he decides to take Kujima with him to retrieve it. To avoid suspicion, Shin has Kujima wear a horse mask and suit as a disguise, and they successfully accomplish their goal. However, on their way back, the teacher happens to run into Kujima...!?