Roddy is a toff, an aristocratic pet mouse whose life is turned upside down with the arrival of Sid, a sewer rat with ambitions. Roddy finds himself spiralling down the plug hole into the underground world of the sewers themselves, after an attempt to banish Sid goes wrong. Whilst Sid enjoys the luxuries of Roddy's smart Kensington flat, Roddy struggles to survive in the pits of the sewers of London.
