The happiness of a young girl and a pony in desperate need of saving depends on the other.
Essie doesn't believe in signs or wishing on stars. She likes facts, and the fact is, she's left her love of horses firmly in the past. She doesn't want a new horse and she certainly doesn't need one, not with the price she'd have to pay. That's a line she just won't cross. But the universe has other ideas.
Essie may not need a pony, but there's a pony that needs her. But taking on a pony without a past brings a lot of unanswered questions, and in searching for answers Essie is going to have decide if to go forward, she is able to forgive the past.