Kevin is brilliant, but his body is so crippled by birth defects that he has to wear braces on his legs. Max is huge and powerful, but he has been so scarred by life that he feels dumb and worthless. Independently, each boy seems like half a person, but when they meet the summer before eighth grade starts, they join together, becoming inseparable friends as Freak the Mighty.

The novel Freak the Mighty tells the story of one defining year in the boys’ lives. It follows them through their first meeting, their summer adventures, their return to school, and even Max’s Christmas Eve kidnapping at the hands of his murderous father. Although the boys are eventually reunited, their happiness cannot last forever. Kevin’s health problems worsen, leading to his death and the end of Freak the Mighty. A devastated Max learns how to face the world without his best friend.

Full of what could be trite or maudlin subject matter—a learning-disabled narrator, a physically challenged boy, a convict father—Freak the Mighty integrates every element smoothly and naturally. The result is a charming, funny blend of realism and fairy-tale dreaming that in the end is very moving.

Max and Kevin met for the first time when they were both in day care. Max was an angry kid called Kicker because he kicked everyone, while Kevin called himself Robot Man because of the leg braces he had to wear. Then Kevin stopped coming to day care, and the boys lost contact until they saw one another briefly in third grade.

The summer before eighth grade, Kevin and his mother moved in next door to Max’s grandparents’ house, where he lived in the basement. The boys meet again when Max helps Kevin get his mechanical bird from the tree where it is stuck. The two boys become friends, and the two families start visiting back and forth.

On the Fourth of July, the boys are on their way to see the fireworks when they run into Tony D. and his gang of teenage thugs. Kevin teases them, and the situation turns potentially dangerous until a police car shows up. The boys have a great time watching the fireworks, with Kevin sitting on Max’s shoulders, but as the crowd breaks up, Tony D. and his friends find them again. Kevin guides Max as the pair runs away, leaving Tony and his gang stranded in a muddy pond.

Max’s grandparents are happy that Max was there to help Kevin (though Max knows it was really Kevin whose quick mind helped him). This starts a happy and extended partnership between the two boys. Every morning, Kevin comes over to rouse Max, who carries Kevin all over town. They have imaginary quests, such as looking for dragons, and as they do, Kevin encourages Max to think, dream, and read. On one of these quests, Kevin guides Max to the hospital’s medical research building, claiming that the hospital staff is developing robot bodies and that when they are ready, Kevin’s identity will be transplanted into one.

Their quests become real one morning when Kevin arranges for Max to get up at three in the morning and dress all in black. Kevin then guides Max to a sewer grate where a purse has fallen. They return it to the owner the next day, which means going into the tenement housing on the far side of the pond, a poor and crime-ridden place. The purse’s owner, Loretta Lee, lives with Iggy Lee, head of a local motorcycle gang. The adults tease the boys a bit and talk to them; they recognize Max because he looks so much like his father, Kenny “Killer” Kane, who is currently in jail.

When school starts, Kevin’s mother gets the school to agree to let Max and Kevin be in the same classes so that Max can help Kevin get around. This is a big change because Kevin is in the advanced classes while Max had been in classes for slow learners. The first time their English teacher calls on Max, the other kids start teasing him. Kevin then climbs up on Max’s shoulders and declares that together, they are Freak the Mighty, winning everyone’s approval.

Soon after this, Max is called to the principal’s office, where he learns that his father will soon be released on parole. Max becomes unhinged and has to be restrained. Later that day, Kevin is eating chop suey in the school cafeteria and has a seizure.

That Christmas Eve, after the two friends exchange their first gifts, Max goes to bed. However, instead of Santa Claus coming to bring presents, Max’s father, Kenny, sneaks into the house and kidnaps Max. Kenny takes him first to Iggy and Loretta’s place in the tenements, then to an old woman’s home nearby. Kenny claims that Max’s grandparents have poisoned his mind against his father, so Kenny keeps Max tied up and explains what Max’s new life will be like.

Because police keep coming around the old woman’s house, Kenny hides with Max in a burned-out building across the alley from the tenements. Kenny ties Max in the basement and then leaves to see if he can get a car. While he is gone, Loretta sneaks in to help Max escape. They have just managed to cut Max free of the ropes holding him when Kenny returns and begins choking Loretta for helping Max. Max attacks his father, screaming that he saw Kenny kill his mother. Kenny turns his murderous attention on Max, starting to choke him.

Suddenly, Kevin shows up with a squirt gun that he claims is filled with acid. He squirts Kenny in the eyes, and while they are burning (from what is later revealed to be soap, vinegar, and curry), Max escapes. Kenny is arrested and returned to jail.

The rest of the school year goes well, but once school is out again, Kevin has a seizure on his birthday. He is taken to the hospital, and it is some time before Max gets to visit. While he is visiting, Kevin has another attack and Max has to leave. When Max returns the next day, Kevin has died. Max is distraught and punches through the glass door to the medical research area. Once he is restrained and calmed down, Max asks Dr. Spivak, Kevin’s doctor, about the bionic body. Max learns that there had never been any plans for one—that it had just been a dream of Kevin’s to help him cope with his condition. Max withdraws from the world, grieving the death of Freak the Mighty for about a year, but he eventually heals as he writes down the story of their adventures and friendship.