The stakes are high in this dazzling and diverse Regency romance, in which a clever duke has made a wager with the now-widowed Viscountess who is the love of his life: To win a second chance with her, he will find husbands for her two sisters—or resign himself to a life of longing.

Scarlett Wilcox is willing to live out her life as a spinster if it means being able to continue her medical research to help a friend in need. After all, few husbands would tolerate her dressing as a man to attend lectures at the Royal Academy of Science. If the Duke of Torrance finds her such a specimen, she'll agree to a marriage in name only, much to the dismay of her elder sister, the Viscountess.

When she's unmasked at a lecture on ophthalmology, Scarlett prepares to be disgraced, but she's saved by Trinidadian-born physician Stephen Carew who claims her as a cousin. Dedicated to caring for his community, Stephen has no wish to marry a frivolous and privileged lady, no matter how many fall for his disarming accent and seductive charm. But Scarlett proves the opposite of any he's ever met before. Yet the pressure to marry blinds them both to the chemistry growing between them, pitting their brilliant minds against their reluctant hearts—as the Duke and Viscountess await with bated breath to see who will win . . . a wager at midnight.