Overprotective mother Vera Cosgrove (Elizabeth Moody), spying on her grown son, Lionel (Timothy Balme), as he visits the zoo with the lovely Paquita (Diana PeƱalver), is accidentally bitten by the fearsome Sumatran rat-monkey. When the bite turns his beloved mother into a zombie, Lionel tries to keep her locked safely in the basement, but her repeated escapes turn most of the neighbors into the walking dead, who then crash a high-society party thrown by Lionel's boorish Uncle Les (Ian Watkin).