It is the first day of teaching for Daisuke Aoki and his third grade class. During the course of the day, he learns about the reasons behind Mimi Usa's extended absence from school. Her absence is due to a long-term harassment by the previous teacher. Neither the other teachers nor her parents believed her, so Mimi's only choice was to quit school. This enraged Rin and Kuro, so they harassed that teacher to the point of causing the teacher to have a nervous breakdown during class and quit. Later, Rin tells Aoki that she hates adults because of that incident.

Aoki decides to be more strict with the students after a fellow teacher commented on his relaxed manner of teaching on the students. Rin knew about it and was not happy about that. It is revealed that Rin was apparently jealous that Aoki went with Kyouko to a family restaurant. The following day, Aoki is absent due to a cold. Rin became worried and went with Kuro and Mimi to visit him.