Nineteenth century Ireland. Blacksmith Gavin O'Malley is a bitter man, with a heart as hard as the iron he forges. He wants his life back—the one that was stolen from him the day his wife died in childbirth—taking their firstborn son with her.

When Aislinn Deirbhile, an immortal, shape-shifting fae, arrives on his doorstep, he knows he's in luck. For Aislinn can give Gavin everything he's been missing: A devoted-seeming wife in the image of his beloved Mairead, and children who are sure to outlive their father. Now, all he has to do is find a way to keep her—without losing his immortal soul in the process.

But Aislinn has an agenda of her own. On the run from a vengeful fae lord who's vowed to either make her his or end her existence, she knows the iron that allows Gavin to take her captive will also keep her pursuers at bay. In order to put herself permanently beyond her enemy's reach, however, Aislinn will need something more. She'll need to win Gavin's heart and convince him to willingly part with a piece of the very soul he's trying to save.