Katie Price's Perfect Ponies: Ponies to the Rescue. Book 6

Jess, Mel, Sam, Amber and Cara are lucky enough to be able to spend as much time as they can with their favourite ponies at Vicki's Riding School. Grooming, sweeping the yard, even mucking out is fun when you love ponies as much as they do. Tragedy strikes when Dumpling, the oldest pony in the stables, dies. Darcy and her friends want to cheer Vicki up and help her raise the money for a new pony, so they decide to go carol singing on Christmas Eve.
It's perfect - there's snow, mince pies and twinkly lights!But on the way home, the girls find themselves in the middle of an emergency and Darcy has to make a speedy late-night ride through the snow to the vet. Will everybody get back safely?