Eleven-year-old Simon Barnes dreams of becoming a world-famous rapper that everyone calls Notorious D.O.G. But for now, he's just a Chicago fifth grader who's small for his age and afraid to use his voice. Simon prefers to lay low at school and at home, even though he's constantly spitting rhymes in his head. But when his new teacher assigns the class an oral presentation on something that affects their community, Simon must face his fears.