Kobayashi and Kasuga used to go back and forth between each other’s houses, but as they grew up, it stopped.
One morning, Kobayashi arrives at school just in time to be late, and runs into Kasuga there.
Kobayashi was called out, but he felt embarrassed to go to school with her, so he turned back the way he came to escape.
After school, Kobayashi was told to clean the gymnasium as a punishment for being late. For some reason, Kasuga was forced to join him.
He tries to get out, but the door won’t open.
The two are trapped in the gymnasium.
Kobayashi took off his jacket as it was hot inside the gymnasium.
Seeing this, Kasuga also took off her uniform.
Kobayashi can’t stop pounding because Kasuga’s chest is so different from before.
Despite her feelings, Kasuga reveals that she is holding back from peeing.
When she heard this, Kobayashi thought he had to do something and looked at the plastic bottle in his hand. When they bantering about the past, they remembered that they had sex together, the situation has became awkward, but somehow it leading to cute confession! way to go Kobayashi!