Lesson 1

Mikoto Ochiai is a high-achieving high school student. Heartbroken, she attempts to take her own life, only to be interrupted by Jin Haiba, a physics teacher.

On her way home from school, Mikoto jumps into a river to save a child and nearly drowns, but Jin rescues her.

On the day of the school marathon, Jin runs alongside Mikoto. Later, when he tries to head home alone with her, the two are caught together by Kazuma Takamine.

Jin comes down with a severe case of the flu. Worried about him, Mikoto visits his house, only to see something Jin never wanted her to see.

Jin and Mikoto haven’t seen each other in a while. When Mikoto goes to a summer festival with Kazuma, Jin secretly follows her in disguise.

Mikoto chooses to keep her distance so she can stay with Jin for as long as possible. But when she becomes upset about missing out on her youth, Jin makes her a suggestion.

As the seasons change, the school cultural festival draws near. With Christmas approaching, Jin, Mikoto, and Kazuma each struggle with feelings that become increasingly intertwined.

As the New Year begins, Mikoto invites Jin to watch the year’s first sunrise with her. However, she soon notices that something seems off about him.

Mikoto reads Jin’s "will". Meanwhile, after learning that Mikoto has feelings for someone else, Kazuma quietly chooses to keep his own feelings to himself.