Makoto Itou has a regular routine of commuting to school via train, often catching a glimpse of the stunning Kotonoha Katsura. His shyness, however, hinders him from approaching her. After hearing of a charm that involves taking a photo of one's crush and setting it as a phone wallpaper, Makoto takes a picture of Kotonoha and continues to admire her from afar for three weeks, hoping for his love to prosper.
One day, Sekai Saionji, who is seated next to Makoto in class, discovers the photo and realizes Makoto's hidden feelings for Kotonoha. She kindly volunteers to assist Makoto with his romantic struggles, successfully connecting the two of them. Makoto is grateful and ponders on how to repay Sekai's kindness, but his gratitude is short-lived as Sekai demands a kiss.
School Days delves into the intricate relationships of these three high school students and the repercussions of their questionable decisions.
