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.