It’s a high school music practical exam time. Although it is clearly stated on the blackboard that singing and rapping are not allowed, Song Ju is showing off her rapping skills regardless. The teacher quietly gives him an F. However, from one side of the classroom, Joo Yeon is looking at Song Ju and making her happy expression. She likes hip-hop as much as Joo Yeon and Song Ju. Song Ju is close to a problem student and lives in a rather underdeveloped multi-family house, while her main character is her schoolboy and lives in an apartment in her wealthy village. Although the two have different grades, environments, and personalities, they work together to form a two-member hip-hop group, Lime Crime.