Through narration, 12-year-old Marty tells the story of discovering his brother Steve is a serial killer when he took Steve’s bowling ball bag without asking and discovered a human head inside. Each week, Marty finds a new head, usually of a black woman, inside the bag hidden in Steve’s closet. Marty keeps the confusing discovery to himself, and immerses himself in a world of watching horror movies and drawing comic books with his best friend David.