Sisters Niki (11), Beth (9) and Lolly (6) have been looking forward to spending the summer holidays with their grandparents and Aunty Anna in the New Forest where they care for and ride their ponies. But excitement quickly turns to dismay when they discover there's a gang of horse thieves nearby. While riding on the open forest with their friends, they realise they are being targeted. After several close encounters with the rustlers, they fear for the safety of their beloved ponies and their herd of wild ponies who live deep in the forest. Will they be able to evade capture or is time running out?