When Cassie Rosse becomes the first woman to train an English Derby winner, with her home-bred horse The Nightingale, she has every right to believe that success is hers at last. Indeed, as she leads in her winner and raises her eyes to heaven, calling to her dead love Tyrone 'We did it!', she knows that this success is as much Tyrone's as it is hers. For it was to his Irish family home of Claremore that he brought Cassie as a young bride, and it is from Claremore that Cassie has at last stormed home to win a place in the history books. Now all she has to do is enjoy her success and retire The Nightingale, since, as a stallion, he is worth millions to her. But life will never be simple for Cassie Rosse, not just because she is unable to move out from the long shadows cast by the early death of her husband, nor because she has an indomitable will to win, but because she has integrity. Against all advice, therefore, she decides to keep The Nightingale in training and race him as a four-year-old, a decision that triggers a set of circumstances which quickly turn her brilliant triumph into a nightmare.
Soon it seems that nothing can reverse the downward spiral of events surrounding her famous horse and its future. It has always been hard for Cassie to stand alone in what is essentially a man's world, but now, with her attentions torn between two extraordinary but very different men and even her family turning against her, she will have to battle hard to keep Claremore, and with it her past with Tyrone and everything that makes her life worthwhile.