When her mother's MS takes a turn for the worse, aspiring Olympian Joannie Edson moves back to Idaho with her aging horse to be closer to home and family. She has given up everything (career, romance) to pursue her goal of riding for the US Equestrian Team, but now, with no horse to ride and no money to buy or support a young prospect, she finds herself faced with a choice: should she take a chance on a relationship with the attractive stranger pursuing her, or invest her time in training her coach's abused and violent mare? As she explores each option, Joannie finds that a fully lived life is much like the jumping courses she's always ridden, every path bearing obstacles that she will have to clear to find her way forward.
Borrowed Horses is inspired by Griffiths's love of northern Idaho, her experience working for the US Equestrian Team, and her devotion to Charlotte Brontë, whose novel Jane Eyre lends Edward Rochester's plot line to this novel.