In this game, based on Aardman Animation's first computer animated movie with 3D graphics, you control a pair of rats: Roddy who is from the posh side of Kensington and gets flushed into the London sewers, and Rita who owns a boat on the sewer named the Jammy Dodger. The evil Toad wants to destroy the rat community of Ratropolis and you must thwart his plan and return Roddy home. Journey through the various settings from the movie in this 3D platformer with 10 levels while using weapons to vanquish foes.

Roddy uses a toothpick as a fencing weapon while Rita can kick and use a bouncing bungee, and the boat has a crayon crossbow. There are power-ups such as Rita's Ruby, a fire extinguisher, and air cannon. There are also minigames you can play against a partner titled Rat Traps & Crayons, Castle Siege and Pathfinder. They allow you to increase your health and unlock exclusive content by collecting and salvaging rare treasures.