The story of a pampered, uptown rat named Roddy who is flushed down the toilet in his penthouse apartment and ends up in the London sewers. In the city of Ratropolis, he meets the lovely Rita, who might-or might not-help him to return home. But first, he must confront the villainous Toad and his henchfrogs who plan to take over Ratropolis. Roddy must learn a different way of life if he's to survive and save the world.