In the still of a snow-covered morning in upstate New York, a girl out riding her horse is hit by a 40-tonne truck. Though horribly injured, both thirteen-year-old Grace Maclean and her horse Pilgrim survive. But the impact on their lives and the lives of those who love them is devastating.
Grace is the only child of prominent New York magazine editor, Annie Graves, and her lawyer husband Robert. In a way which none of them at first understands, their destiny comes to depend upon Pilgrim's. So mutilated and traumatised is he that even the vet who saved his life now wishes he hadn't. Annie refuses to have him destroyed, sensing that if she does, something in Grace will die too.
Annie hears about a man in Montana, a 'whisperer' who is said to have the gift of healing troubled horses. Abandoning her job, she sets off across the continent, with Grace and Pilgrim, to find him. The man's name is Tom Booker and he lives on the Rocky Mountain Front, a place of daunting beauty. Here, under the massive Montana sky, all their lives are changed forever.