During a high school music exam to assess the singing abilities of students, Songju shows off his rapping skills despite the blackboard in the background stating that pop and rap songs are not allowed. The teacher gives him an F on the test without saying anything. In the meantime, on one side of the classroom, Juyeon looks happy, watching Songju rap. He loves hip-hop as much as Songju does although these two come from completely different backgrounds. Songju is a troubled student living in a multi-house home in a less developed area while Juyeon is an exemplary student living in a fancy apartment in a rich village. Despite differences in grade, personality, and background, they decide to form a hip-hop duo called LIMECRIME.
Seong-cheol is a high school student who grew up neglected. In order to make money in a harsh society that abandoned him, he teamed up with Gi-joon, who is two years younger than him, to use his status as a minor to make money and seek a big blow. A father who left home, a sick brother and a mother whose cares for him. Seong-cheol, who was abandoned in hellish reality, starts a desperate survival in his own way.
Young-in was brought back to life by his mother with the help of AI. However, the sweetness of seeing his son again didn't last so long. But soon, his mother realizes that the AI ‘deleted’ Young-in’s consciousness and has been pretending to be him.