Boy is a Mapusaurus roseae chick, a baby theropod dinosaur who must grow up fast to survive in the mid-Cretaceous. After an adult Mapusaurus destroys his family, he runs for the debatable safety of the forest. Brushes with other creatures, including the crew of the USS New World, are all part of the learning curve as he strives to carve out a territory of his own and grow strong enough to eventually face down his arch nemesis.

MAPUSAURUS is the second New World Series tie-in short story and takes place during DINOSAUR – Book 1, and REVENGE – Book 2.