In 1835 Paris, a tense arrangement unfolds as the Vicomte de Prony visits La Vellini, a beautiful kept woman of Malagan birth, and delivers a blunt message: her long-standing affair with the libertine Ryno de Marigny must end because Ryno is about to be married. On his way out, Prony crosses paths with Ryno, who has decided to visit his mistress one last time. After their reunion, Ryno declares that their relationship is finished, though La Vellini remains doubtful. In the background, the Marquise de Flers, grandmother to Ryno’s prospective bride Hermangarde, and the Comtesse d’Artelles—the wife of Prony—converse about the upcoming nuptials. The Marquise believes the match will profit both Ryno and his innocent bride, while d’Artelles harbors doubts that the penniless rake can truly leave his libertine past behind. As the pair depart, the Marquise hints that Ryno has had a mistress for a decade.
The cast of the household shifts to a dramatic backstory. A decade earlier, Ryno lives a carefree aristocratic life in Baden until a fateful encounter with La Vellini, the wife of an elderly baronet, Sir Reginald. Ryno is instantly drawn to her, but she spurns him at first. A ride in the Bois de Boulogne leads to a failed kiss and a duel challenge from Sir Reginald. Ryno attempts a chivalrous dupe to end the duel, but Reginald shoots him, leaving him gravely wounded. As Ryno lies recovering, Vellini appears and licks the blood from his wound, sparking a torrid affair. Over the next two years, Vellini visits while Ryno convalesces, and eventually leaves her husband, causing a scandal in Paris.
The lovers relocate to Algeria, where they live together and have a daughter. Their daughter's death—she is stung by a scorpion—drags them into a profound grief, and they even confront mortality in a vivid moment: they make love beside their daughter’s pyre. Back in France, the bond between them remains fraught with tension; they acknowledge mutual loathing in the wake of the tragedy, yet the lure of each other continues to pull them closer. Eventually, Ryno’s feelings for Vellini ebb, and his appetite for their relationship wanes.
Having heard Ryno’s tale, the Marquise de Flers allows the marriage to proceed. The newlyweds, Ryno and Hermangarde, move away from Paris to a castle on the Norman coast, where they enjoy a short period of conjugal bliss. Hermangarde becomes pregnant, and for a time the couple seems settled. Yet the shadow of Vellini follows them. One day, while Ryno takes a solitary walk, Vellini appears again, pressing him to either kill or kiss her. They share a kiss, reigniting the affair even as Hermangarde mostly remains with child in the castle.
As the affair deepens, Hermangarde grows uneasy, noticing Vellini lingering near the estate. One night, she makes a bold move and goes to Vellini’s house, where she discovers her husband and Vellini in the act. The next morning, Hermangarde suffers a miscarriage, a devastating blow that shakes the young wife’s world. The narrative now shifts to Paris, where the Vicomte recounts to the Comtesse that Ryno has resumed a regular—indeed open—visitation of Vellini, displaying a striking indifference to his wife.
In the end, the Comtesse’s wary judgment finds some relief in the passing of the Marquise de Flers, who never had to witness the unraveling of the union she once orchestrated. The story remains a measured, intricate portrait of desire, loyalty, and the inescapable pull of a past that refuses to stay buried.
