Mouseheart

After escaping his Brooklyn pet shop, a mouse named Hopper finds his way into the subway tunnels beneath York City and discovers a rodent civilization previously unknown to him, including Atlantia, a utopian rat civilization. But Atlantia is not all it seems, and Hopper soon finds himself caught in an epic battle that spans generations and species, and learns terrible secrets about Atlantia and his friends, and a powerful secret about himself.