Marcus is the narrator and protagonist of the story. He is a 14-year-old eighth grader who is unusually tall and mature-looking for his age. He has wide, brown, oval-shaped eyes, curly brown hair, and a complexion that darkens in the sun, like his Puerto Rican father. Marcus was born in Puerto Rico, but his parents moved to a suburb of Philadelphia when he was two. His father abandoned the family when Marcus was four years old, leaving Marcus to help his mother look after his younger brother, Charlie, who has Down syndrome. Marcus also surreptitiously helps his mother financially by running several businesses, such as walking kids to and from school. He is kind and empathic, but because he has been teased about his size his whole life, Marcus assumes that people are afraid of him. Consequently, he is introverted and always on the defensive. Because Marcus knows his size can appear threatening, he never reacts to being taunted by bullies. However, the one thing that triggers a powerful reaction in Marcus is Charlie being bullied. The Puerto Rico trip is a result of Marcus’s losing control when Stephen, the school bully, refers to Charlie using a derogatory word.