Rap and comedy combine to tell a tale of sibling rivalry. Rookie teacher Nathan Carter starts his first day back at Elmsbury High School where he was once - well - not the best kid in the class.

Nathan is on a mission. He wants to connect with all the kids who have problems and who he thinks he understands because he used to be one of them. He takes charge of the euphemistically-named 4 O'Clock Club.

It's really the detention class, and to his surprise he discovers that the king of the club is his 13-year-old brother, Josh. Josh is in denial that this uncool, elbow-patched, fresh-faced teacher is his brother. He has told all the other 4 O'Clock Clubbers that his brother, Natty C, is a famous rapper.