Comedy about a girl called Catherine Walcott. And another girl called Catherine Walcott. Sisters who had no idea the other existed until their father dropped dead. Cathy has a fiance, a Duke of Edinburgh Award and a pension. Cat has a pay-as-you-go phone. The only things they have in common are their names (a smart move if you have got a secret daughter). Both of them have always wanted a sister - just maybe not each other.

Cathy is forced to take compassionate leave from work but can't bear to tell Tess, so Cat let's Cathy hide at her house and throws her a party to cheer her up.