Purple Hills (A Woodlea Novel, #4) by Alissa Callen

Sibylla Elliott's return to small-town Woodlea will only be temporary. The audiologist will reassure herself that her father is doing well after his stroke and then be gone before her stepmother can wedge herself any further between them.

Single-dad Hugh Mason's entire world is his freckle-faced, space-obsessed son, Riley. When Hugh suffers a head injury, he has no Plan B, until Riley and his miniature pony come to his rescue, fetching their neighbour Sibylla. Glad to escape the tension in her family home, she moves to the next-door farm to help out the local horse chiropractor.

But when close quarters magnify the attraction between Sibylla and Hugh and refreshes past heartbreak, there is a price to pay. Will the wish of a motherless five-year-old as he stares at the night sky be enough to make Sibylla's plans permanent?