Ten-year-old Hercules Amsterdam is a human boy no taller than a mouse standing on its hind legs. So when he discovers an amazing city just behind his bedroom wall, illuminated by a cheese sun and populated by friendly mice, he decides to stay there. But soon Hercules stumbles upon evidence of an enemy that lurks within the walls. When the mice refuse to believe his warnings, it's up to Hercules to save his friends from a terrifying, destructive force-a...