Max has lived with his grandparents ever since his father murdered his mother. He lives in the basement partly because he likes his privacy and partly because Gran and Grim are a bit afraid of him. Max is very large for a boy of 12, and he looks a lot like his criminal dad. He is shy to the point of silence; people think he has intellectual disabilities. Max tends to agree, and he also worries that he might become evil like his father.

Max befriends Freak, a boy with a serious physical disability, and warms to Freak’s energy, smarts, and snarky sense of humor. They have many adventures together, Max carrying Freak on his shoulders, and they become the duo known as Freak the Mighty. During these exploits, Max begins to realize he’s as smart as other people but simply has trouble reading. Freak’s interest in many fields of study inspire Max’s curiosity, and he begins to take an interest in school. He also becomes aware of an emerging compassion for other people, including his grandparents, Freak’s mom Gwen, and Freak himself.