Kevin and Max are the two main characters in Rodman Philbrick's teen novel. Both boys face physical and mental challenges during the course of the story, and they discover that working together can be a benefit to both of them. Maxwell Kane is the narrator, a very large boy who lives with his grandparents. Max has issues with his ever-growing body, but his mental state is a more serious problem. As a little boy he witnessed the murder of his mother by his father, Kenny "Killer" Kane; shortly afterward he first met Kevin at day care. Kevin suffers from a disease which has left his tiny body twisted and deformed. But Kevin's physical limitations have not affected his brain: He is a genius with an unlimited vocabulary and a fascination for knights and dragons. When Kevin and his mother, The Fair Gwen, move in next door to Max, the boys become friends. Soon they come up with an idea: Separately, the two boys face the daily challenges that might be expected of two such unusual individuals. They are bullied and stared at, and they have problems getting around. But together, the boys discover, they can combine their strengths: When Max hoists Kevin upon his shoulders, it solves the problem of Kevin's mobility. With an expanded new view of life, Kevin gives orders from above, and Max doesn't have to worry about the decisions he must make, trusting that Kevin's calculations will be the right ones. Together, they become "Freak the Mighty." The tandem twosome grow stronger through their friendship, and Kevin is able to experience adventures he had only previously imagined. Max realizes that

I never had a brain before until Freak came along and let me borrow his for a while.  (Chapter 1)

Max is so inspired by Freak that he decides to put "the unvanquished truth stuff down" on paper. After "months and months" in the down under, Max emerges with a new outlook on life and a book that relives the tales of Freak the Mighty.