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.

Hannah and Helen are in heaven - there are so many cats to care for at Stonelea, and they're no trouble at all. Except for Mitch - an adorable black and white kitten with a nose for adventure. Now Mitch has escaped from the sanctuary - last seen heading for town! Where on earth can he be? Mitch's new owners are due to pick him up on the very day he escapes - can the twins track him down before they arrive?