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 and Cat cannot find their dad’s will and, at their joint birthday party, their mums war over which family their dead dad loved most.

Cat decides to take Cathy on their own sister honeymoon to cheer her up. Marilyn finds Colin’s missing will and, together with Tess, they need to tell the girls the shocking news.