Outcast and alone, Thomasina MacDonell is hell bent on finding her brother, the only person who can thwart their father's latest scheme to offer her as payment for his gambling debts. Disguised as a lad, she defiantly sets off on foot to locate him—never expecting to find a handsome, Irish warrior riding her beloved horse. The warrior's offer of help and unsolicited advice on how to be manlier sparks an intimate desire to reveal her more feminine side.

Rejected by the love of his life, Sean O'Cisoghe wants simply to return home and heal his broken heart. When a young "lad" steals the horse out from under him, he discerns the spirited woman may be in way over her head against her ruthless father. Finding her brother while keeping her would-be betrothed at bay, Sean must confront the fact that Thomasina has stolen his heart. Will Norman soldiers out for his blood and shifting clan alliances cut short their growing passion?