Hippo, a peculiar adolescent, and his Hungarian step-sister Buttercup struggle to come of age in late 1990s America, under the roof of a mother who has been institutionalized at least once.

Hippo examines the coming-of-age of two step-siblings: Hippo, a video-game addicted teenager and Buttercup, a Hungarian Catholic immigrant with a love of classical music and Jesus. Like the Ancient Greek Aphrodite, Buttercup's love is unrequited by a brother who prefers to indulge the art of war and chaos. The result is a hormone-fueled, tragicomic waking nightmare that must be seen to be believed.