Sana Sana is in her second year as a teacher. This is her first time as a homeroom teacher, and she has been busy preparing for classes late into the night every day. As Sana is preparing materials in the deserted library as usual, the janitor Sugiura calls out to her with an intrigued look on his face. Sana cannot hide Kokoro of Sugiura, who has not had a very good reputation. However, Sugiura shows up at the library again with an eye on Sana...