Augusta and Christina ride again in the fourth part of the series.

Augusta's mother has gone to hospital to have a baby, and Augusta and Christina are staying in the cottage with a French girl to look after them. Mignon bails out pretty much as soon as Augusta's mother has gone, but the girls think they'll cope.

Then something happens neither of them expect. A runaway boy and his pony turn up in the stables. Their first instinct is to ring the police, but they listen to Nico's pleading. He's desperate for his mother to come back and find him, and almost as desperate for his father not to sell his pony. Nico's father says she's only a pony, after all.

This decision has far-reaching consequences as Augusta wrestles with the prospect of being a sister, dealing with her aunt and her cousins, and trying to decide what to do with Nico. And his pony.

This book was written nearly 30 years after A Pony to School, and its tone is quite different to the earlier books in the series. But Augusta is growing up, and we can see that and sympathise with her dilemmas.