The hero, Kieran, has recently moved to London from Barbados, where he and his siblings had a terrible childhood with their abusive uncle, but managed to survive and prosper with a shipping business after his death. Now Baron Rothewell, Kieran is left alone for the first time after his sister marries (in the previous book); he is an outsider to London and to its society. When he sees the child of his beloved cousin, he feels a niggling desire for a family of his own, despite thinking himself too damaged for a true relationship. He spends most of his time drinking and gambling in low places, to distract himself from a deep guilt he carries from his past. At the book's opening, he's just had bad news of some sort from a doctor he visited, related to spasms of intense pain in his abdomen.
The heroine, Camille Marchand, is the bastard child of an adulterous relationship between her mother and a sleazy French aristocrat with no money; she's always been an outsider. After her mother's recent death, she learns that she has a sizable inheritance from her grandfather, provided she marries and has a child within a specified time, now fast approaching. She also wants a child of her own, more than she admits aloud. Though she has misgivings, she goes to her father in London to ask his help in finding a husband, but since he is barely accepted in society, her choices are limited, and culminate in her hand in marriage being offered as the prize in a card game. Worse, her mother's husband (who divorced her) is also still in society. Kieran is playing against a man whom he knows to be much worse than he is, not to mention that he's intensely attracted to Camille as soon as he sees her. So he manuevers to make sure he's the one who wins her, and Camille is smart and practical enough to realize he's her best chance.
All of these factors twist together into delicious tension between the two of them; their marriage of convenience is logical, but neither of them can admit at first that they want it to be much more. Family and friends gently suggest there should be more than convenience, only to be shot down. Kieran and Camille give in to their lust for one another in the midst of all the conflict, making it worse (though the position in which Camille loses her virginity was the only what?! moment in the book for me). I loved the difficult path they followed to love.
There was some series-itis with recurring character Kemble, whose first name ought to be Deus ex machina, and the Relationship Talks between the hero and his family, who featured in earlier books. I also predicted one final plot twist way ahead of its actual appearance. But I forgave those things for the angst and the theme of finding family where you least expect it.