The death of Captain Jack Ryder's father, the Duke of Stamford, leaves Jack restless. The Duchess' spiteful relatives have made his life a misery, and he wants nothing more than to escape London for a time. Dressed in buckskin breeches, he takes to the road on his horse, Arion, with the intention of visiting his mother's grave in Ireland. But after only one day on the road, events conspire to interrupt his plans.
Jack finds himself not only caught up in a conspiracy of immense proportions, but also in a passionate love affair with a lady he cannot marry. Lady Ashley Lambourne's father, the Marquess of Butterstone has been murdered, and Jack promises to find his killer.
Meanwhile, a close friend of Jack's from his army days, Harry Feather, heir to one of the largest fortunes in England, faces an arranged marriage to Lady Erina Roundtree. A tall half-Irish beauty, Erina is a spirited lady, who makes it plain she doesn't wish to marry Harry, either. Determined to enjoy a quiet existence after his years fighting Bonaparte, Harry fears Erina will run him ragged. Why he is indulging Erina in one of her harebrained schemes is beyond him, when he should marry a quiet woman like Miss Beckworth.