East Side, West Side 1949

Set shortly after the end of World War II, the film opens with a voiceover by Jessie Bourne, Barbara Stanwyck, a New York socialite who presides over the refined Gramercy Park area on the East Side. She suspects her lawyer husband Brandon Bourne, James Mason, of infidelity. Years earlier, his affair with party girl Isabel Lorrison had nearly broken their marriage; now Isabel has returned, escorted around town by Alec Dawning, a man with a short fuse. When Dawning spots Isabel with Brandon, he knocks him down outside a glitzy nightclub, and the punch is recorded by a tabloid photographer, thrusting Brandon into the front pages and turning the city’s attention toward their tangled lives.

Jessie becomes acquainted with Mark Dwyer, a former cop and recently returned U.S. Army intelligence officer who grew up in the same rough West Side neighborhood. Although they share a long-standing, quiet attraction, their relationship remains purely platonic as they navigate the postwar climate of suspicion and social expectation. One afternoon, Jessie asks Mark to drive her to a Washington Square apartment. He waits outside, unaware that the apartment belongs to Isabel, and Jessie has gone inside to confront the woman about the affair. The meeting devolves into a heated quarrel, and Jessie leaves with a heavy heart, the tension between ambition, loyalty, and desire hanging in the air.

Later that afternoon, Brandon goes to Isabel’s apartment and learns she has been killed. He reports the murder to the police and leaves a message for Jessie to call him back at Isabel’s place. When she does, he shares the grim news, and the investigators arrive to unravel the mystery. Jessie arrives with Dwyer, an old colleague of the detective in charge, and Dwyer takes the case into his hands, convinced that neither Jessie nor Brandon is the killer. The investigation hinges on a single clue: a broken fingernail found at the scene, which Dwyer follows with patient, steady method.

As the plot unfolds, Dwyer’s persistence begins to peel back layers of jealousy, deception, and postwar disillusionment. The pursuit leads to a startling revelation: Felice Backett, Alec Dawning’s jealous girlfriend, is connected to the crime, thereby clearing Jessie and Brandon of responsibility. The truth emerges through careful deduction rather than sensational headlines, and the narrative sharpens into a moral reckoning about trust, forgiveness, and the cost of secrets in a society rebuilding itself after conflict.

In the final act, Brandon pleads with Jessie to salvage their marriage, appealing to shared history and the possibility of a future together. Yet Jessie, having faced the unraveling of more than one relationship, walks away, choosing independence over a relationship strained by betrayal and fear. The film closes with a quiet, unresolved note about love, loyalty, and the price of truth in a world still haunted by the aftershocks of war.