The only escape Martin Taper has from his miserable life as a pet store clerk is his diorama, a fantastical playset populated by miniature heroes, villains and monsters. Frustrated with his bullying manager and an unrequited crush on a beautiful co-worker, Martin acts out his fantasies nightly in the diorama, never imagining that any of them will come true. But when he invites a strange young boy into his world Martin's luck suddenly starts to change, and soon finds that the diorama may have a mind, and a vengeance, of its own.