Narrowly escaping a circus tragedy that leaves her orphaned at age seven, Italian immigrant Willomena (Willow) Antoniette seeks refuge at The Manor of Diversions—a holiday resort in England born of a ghost story. For eleven years thereafter, she’s raised alongside the children of the resort’s owners: Julian, his twin brother, Nick, and their younger sister Emilia. While Willow dreams away her days imagining Julian and herself are the hero and heroine of The Butterfly’s Mistress, a sensual novel being penned by Emilia, her worst nightmare looms as her guardians prepare to send her to a finishing school where she’ll be groomed for the upcoming Season’s marriage mart. It would do little good to tell them she's already found the only man she'll ever marry, when Julian thinks of her as nothing but a friend.
As a machinist and engineer, nineteen-year-old Julian Thornton prefers the predictable life. His ever-deepening affections for Willow present an unwanted distraction to his carefully calculated plans: to build an amusement park that will lure a younger, wealthier clientele to his father’s resort. On the day of Willow’s departure to finishing school, Julian sets off on a transatlantic ocean liner to seek investors at the St. Louis World’s Fair, where tycoons are slated to gather from around the globe. Utilizing her circus talents, Willow stows away on the selfsame ship, determined to secretly watch over Julian while avoiding a loveless marriage. But her plans come to an abrupt halt when a tiny, mute orphan named Newton—chasing a pair of 18th century Italian shoes possessed by a vindictive female ghost—brings Julian and Willow face to face.
Following an explosive reunion, Julian and Willow embark on a journey across the transatlantic and St. Louis, forced to face their true feelings and solve the mystery of Newton and his ghostly companion. Unbeknownst to anyone, the haunted shoes hold the key to Willow’s own tragic past, and soon Julian, Willow, and Newton become unsuspecting pawns between the ghost and her murderer in a karmic game of cat-and-mouse that could cost all of them their lives…