Roddy St. James is an upper crust pet mouse living with his human family in a Kensington flat. While his family is away on vacation, a sewer rat named Sid comes out of the sink and decides to make himself at home, especially since England will be Playing Germany in the World Cup Final. Sid then flushes Roddy down the toilet which he claims is a Jacuzzi, and he comes upon a city in the sewers. In the sewers he meets a scavenger rat named Rita who tells him about her archenemy, the Toad who has a plan to flood the sewers at the halftime of the World Cup Final, when everyone flushes their toilets, so he can drown the rats, flood the city, and take over the sewers. Roddy and Rita must form a team and work together to overthrow the toad before his plan succeeds.