Francis, an aging, successful writer of crime novels, travels to Venice with a clear plan: find a quiet, year-long residence to focus on a new novel. His search leads him to Judith, a real estate agent who insists on showing him a unique house reachable only by boat on the island of Sant'Erasmo. From the moment they meet, Francis is smitten by Judith’s beauty and vitality, a former model many years younger than him, and he agrees to rent the place only if she moves in with him.
Eighteen months pass, and Francis and Judith are happily married, living their life on Sant'Erasmo. Yet the peaceful setting does not translate into creative peace for Francis. Writer's block gnaws at him as he wanders the winding streets and canals of Venice, seeking a spark for his next novel. His world grows more complex when his adult daughter Alice arrives, accompanied by her ten-year-old daughter, Vicky. Alice, no longer with the father of her child, Roger, is an aimless aspiring actress trying to find her footing. During a day together, Alice and Judith swim, but Alice disappears while they are in the water, drifting away in the opposite direction. Vicky, left behind, is taken in by Roger, her father. To untangle the mystery and help, Francis hires Anna Maria, a vodka-fueled private detective who once had a lesbian relationship with Judith.
The truth about Alice soon emerges: she is entangled in a passionate affair with Alvise, a penniless aristocrat who also deals heroin on a smaller scale. Months slide by, and Francis’s writer’s block remains stubbornly persistent. The strain of his marriage grows as Judith’s work during the peak season demands more of her time and attention. Jealousy creeps in, and Francis begins to suspect Judith’s fidelity. He discovers that, even before they met, Judith had relationships with people from both sexes, a past that complicates their trust. In a controversial move, he arranges for Judith to be followed by Jérémie, Anna Maria’s son who has just left prison. This intrusion triggers a volatile turn: Judith ultimately sleeps with the young man when she discovers the surveillance.
As the marriage falters, Judith leaves Sant'Erasmo and returns to Venice, leaving Francis to face the unsettling truth of their fractured bond. Autumn brings a harsh turn when Jérémie is attacked by a gay man who kills his beloved dog in retaliation. Francis lashes out at Jérémie for his earlier behavior, and Jérémie, in a moment of despair, slashes at his wrists. Francis intervenes in time to save him. In Paris, Anna Maria returns with troubling news: Alice has sent a disturbing video of herself in a sexual encounter with Alvise. Anna Maria also reveals she is dying from terminal lung cancer, shifting the emotional weight of everyone around her.
Winter settles over Venice as Alice returns, and it becomes clear that Alvise is now in prison. Judith welcomes Alice back, and Francis and Alice begin to repair their relationship, though Alice remains resolute in her love for Alvise and candid about the fact that her daughter may be better off with her ex-husband Roger. At Anna Maria’s funeral, a tense moment erupts when Francis lashes out at Jérémie for his apparent emotional coldness toward the dying friend. The two men reconcile when Jérémie, preparing to leave Venice to forge a new path, says goodbye to Francis with a sense that youth still holds possibilities.
In the end, Francis completes his novel, finally finding a sense of purpose that had eluded him for so long. He realizes he has no reason to stay in Venice and makes a decisive move toward a future beyond Sant'Erasmo. He races to find Judith, asking her to move with him to Paris, seeking a fresh start together in a city that could cradle the next chapter of their lives.
