The year is 1383, and the Wolf of Badenoch has conducted a terroristic campaign across the highlands to increase his wealth and land holdings. Now he's turned his sights from Scotland to the Kingdom of the Isles. Seeking to keep the Wolf’s superior fighting forces out of his island nation, the King of the Isles turns to Chieftain Hector MacLean for help. A survivor of the Hundred Years’ War, Hector’s reputation precedes him. Brutal, clever, perhaps the greatest warrior Scotland or the Isles has ever produced—as if the man has a gift for killing. But after changing his life, Hector has no interest in returning to his old ways. As an alternative to war, he agrees to forge a marriage alliance with one of the Wolf’s allies, hoping to gain their fidelity and protect his family and clan.

After surviving a brutal first marriage, young Irish widow Cara O’Ballevan arrives in Lochbuie Clan Territory, her sole prayer to make a peaceful home with the MacLeans, but the clan is wary of her as an outsider. After praying for help, she happens upon a kind man beneath a bright moon, unaware that he is the chieftain and soon to be betrothed to another. Over a series of meetings, Hector and Cara help one another, encourage one another, and begin to come to terms with a past they’re both trying to leave behind.

When Cara faces a threat during a clan dispute, Hector discovers that the deadly combatant he used to be isn’t gone, but lurking just beneath the surface. This time, the lethal warrior within him takes up watch over Cara. As her gentle spirit roots deep into his heart, Hector knows she can never become his wife. A future with her could only lead to war and disgrace. Yet he cannot stop himself from falling in love with the one God entrusted to him – the woman he isn't supposed to marry.