After his usual night of drinking at the local pub, Hubert Flynn (Pete Postlethwaite) returns home and transforms into a rat. Hubert's family each have different views on him now that he became a rodent. His wife Conchita (Imelda Staunton) thinks that this change is supposed to be a lesson to Hubert and that the reason he transformed is his own fault. Their son Pius (Andrew Lovern), destined for a religious life, feels that because his father is now an animal, his family should kill him. Their daughter Marietta (Kerry Condon) feels that the rat is still her father and that they should treat him with love and respect.