Makoto, a high school student, develops a crush on Kotonoha, a girl he sees on the train.
Too shy to approach her, he secretly keeps her photo as his phone's wallpaper, hoping it will bring them together.
Sekai, a classmate, discovers his crush and unexpectedly offers to help him connect with Kotonoha.
The three of them form an unusual friendship as Makoto navigates his feelings for Kotonoha with Sekai's assistance.
School Days follows their intertwined lives, exploring the complexities of teenage relationships and emotions.