The story revolves around Adam Lyon, a human. After a clerical error listed his surname as "Lion", Adam is forced to transfer from Chester Arthur Middle School to Charles Darwin Middle School, a school for local zoo animals. Shortly after his transfer, he is partnered with Jake Spidermonkey in gym (hence the title). While Jake enjoys having fun at the expense of others, he quickly becomes attached to Adam. The majority of the show's humor derives from Adam's attempts to reconcile his human limitations, as well as his outsider status, with the demands of an animal-centric school and social scene.