When 11 year old Abi Foster's mum asks her if she'd like a brother or sister, Abi expected a baby, not a tough little extrovert called Sam!

But Abi is thrilled to have someone to play with, and though Sam seems a little headstrong - not to say bossy - at first, Abi's the kind of girl who gives everyone a chance and Sam is the sister she's always longed for.

But when Sam keeps buying expensive presents for them, Abi and her parents smell a rat - where on earth did she get the money from? And then there are the stories she tells about her real dad - if he's so great, why is Sam being fostered? Sam's bubbly nature is hiding a desperate need for love, attention and stabiltiy and Abi wants to help - more than anything.

Gradually Sam and Abi break down the barriers between them, and Sam has a loving family at last.