Stonelea Cat Sanctuary features in several of the existing Home Farm Twins titles, and is run by elderly spinster Lucy Carlton. When Lucy has an accident, she is laid low for several weeks and can't manage all the cats on her own - so the twins move in to help during their school holidays. Every day they are up early at the sanctuary, helping out with abandoned and injured cats and kittens - each with their own special story.

The twins are learning how to hand-rear a litter of five abandoned kittens. All the kittens are thriving now, except for little Maisie. Tiny, and getting scrawnier by the minute, Maisie is a real worry for Helen and Hannah. It's obvious she needs her mum, but can the girls trace her, wherever she is, before it's too late?