Alan Quinton, Joseph Cotten is an American soldier in Italy during World War II who spends his downtime writing letters to his friend Roger Morland, a man who freely admits he “never had any standards, manners or taste.” Through these letters he becomes fascinated with Victoria Remington, a woman he has never met, whom he regards as a kind of “pin-up girl of the spirit,” a muse he can pour out feelings he would never voice aloud. He fears Victoria will be disappointed by the real Roger, who soon departs for paratrooper training in England—and, on leave, to meet Victoria—after Alan confesses his romantic illusion. In the meantime, Alan’s own service ends with a grave wound on the Italian front, and he learns that Roger is dead, a revelation that shatters his world and unsettles his engagement to Helen Wentworth, Anita Louise. He retreats to his aunt Beatrice Remington’s Essex farm, hoping to find quiet after the chaos of war.
In London, a brotherly nudge sends him to a party where he encounters Dilly Carson, Ann Richards, and a woman who calls herself Singleton. Mitchelling the liquor with sorrow, Alan blurts out the truth of the letters and the illusion he’s built around Victoria; Dilly quickly grasps that the “Victoria” of his reverie is the very Victoria he’s never met. She hints at a murder connected to the letters, and the night ends with a realization: Alan and Helen realize they are no longer in love, and they part on cordial terms as Alan heads to the Essex farm, seeking a life away from the past. There, a sign for Longreach—the farmhouse where the letters originated—pulls him toward the truth: Victoria died more than a year before, and Roger Morland was murdered by his wife. Guilt gnaws at Alan for ever having written the letters that helped shape an entire romance out of thin air.
Back in London, Dilly reveals a chilling twist: Singleton is actually Victoria, who has fallen into amnesia and cannot see that the woman in her memories is herself. She begs Alan not to tell Singleton that he wrote the letters, for Victoria formed a love for Roger through them and even married him for that imagined connection. Dilly recounts the night of the murder: Victoria, memory impaired, stands with the murder weapon in hand as Roger dies, and the truth of what happened refuses to come clear in a courtroom. Victoria is declared insane and placed in a psychiatric hospital for a year before being released into Dilly’s care. Victoria never fully recovers her memory, continuing to live as Singleton, the foundling who believes Alan’s love is for another woman she herself cannot name.
Eventually, Beatrice Remington, Victoria’s adoptive mother, gives her blessing for a marriage between Alan and Singleton, now aware that Singleton is Victoria herself. Yet the marriage remains troubled by Alan’s lingering memory of a woman other than Singleton. Beatrice returns to the farm, and Singleton begins to unlock the buried memory during a drive to Longreach. Conversations with Beatrice stir suppressed recollections: Victoria and an intoxicated Roger argue as Victoria rereads the letters, trying to recall the man she loves rather than the bitter figure before her. Roger reveals he did not write the letters, and his disdain grows violent, striking Victoria. Beatrice intervenes with a knife and stabs Roger, saving the precious letters he had thrown into the fireplace.
As Alan arrives at the country house, Victoria’s memories surge back, revealing her true identity and, crucially, that Alan was the author of the very letters that linked their lives. In that poignant moment of recognition, Victoria realizes the bond she had with the man behind the words, and the two finally exchange a kiss, choosing each other after a lifetime of misremembered echoes.