Kim Seungmin

Y/N is a high school student and a professional archer. She grew up in an orphanage with her twin brother, Park Won-seok, who was later adopted by a wealthy family. During their latest video call, tragedy strikes: Won-seok dies after falling from a window at Yeontan High School in Seoul. The police quickly rule it a suicide, but Y/N is convinced her brother was brutally murdered.

In search of the killer and revenge, Y/N transfers to Yeontan High School. She deliberately conceals her relationship with the deceased so she can conduct a secret investigation alone among her new classmates.

Seungmin, a charismatic but secretive boy, also attends the same school. He is forced to single-handedly provide for his gravely ill mother and is battling a fatal brain tumor that causes memory loss. Unable to bear the pervasive school cruelty, Seungmin decides to secretly take justice into his own hands, harshly punishing bullies and protecting the weak.

The story begins on Y/N's first day of school. She's speeding confidently toward her new school on her old motorcycle. Suddenly, Seungmin starts crossing the street in front of her. Noticing the pedestrian at the last moment, Y/N swerves to avoid an accident. The motorcycle skids, she loses control, and crashes full speed into a pile of trash on the side of the road, to Seungmin's shocked gaze.