In its original webtoon edition, it is a tetralogy with each part referencing one of the four temperate seasons (spring, summer, autumn and winter), featuring the stories of teenagers and young adults who experienced the tumultuous age of youthhood.

Set in spring at Cheongseom High School, Part I centers on 18-year-old girl Yoon Bo-mi who is conflicted between her crush on Lee Jae-min and her friendship with Kang Sun-hee.

Primarily set in Cheongna University during the following autumn, Part III centers on 24-year-old college student Jin Ga-eul who apparently confesses her feelings to a man named Kang Soo-bin.

Returning to Cheongseom High School and set in the following winter, Part IV focuses on the constant suffering of 18-year-old boy Park Dong-chae who is being harshly bullied by Cha Woo-jae and his gang.

As Dong-chae's tormentors gradually drive him over the edge, his 16-year-old younger sister Park Eun-chae secretly sets out to save him from further bullying, asking her crush Lee Jae-min for help.