The Fortune Hunter by Daisy Goodwin
In 1875, Sisi, The Empress of Austria is the woman that every man desires and every woman envies. Beautiful, athletic and intelligent, she has everything – except happiness. Bored with the stultifying etiquette of the Hapsburg Court, Sisi comes to England to hunt and to find excitement. There, she discovers the dashing Captain Bay Middleton, the only man in Europe who can outride her. Ten years younger than her and engaged to the spirited Charlotte, Bay has everything to lose. But Bay and the Empress are as reckless as each other.