Peggy Evans, Lana Turner, a bored and unhappy soda jerk in Hotchkiss Falls, New York, bets her co-worker, Pamela Blake Mitzi, that she can serve ice cream sundaes while blindfolded. She is reprimanded by the store's new general manager, Robert Young Bob Stuart. An agitated Peggy leaves what appears to be a suicide note at her boardinghouse and disappears, leading locals to suspect Bob drove her to end her life. Unbeknownst to locals, Peggy has in fact fled to New York City, hoping to start anew.
Upon arriving in Manhattan, Peggy spends her life savings on a glamorous makeover, but while standing outside a newspaper office, a falling paint can knocks her unconscious. Durstin, Eugene Pallette, a publisher at the paper, assumes Peggy is suffering amnesia and takes her in, running her photo in the newspaper. Durstin jokes that Peggy could be a kidnapped heiress, which sets Peggy on a new course. She visits the library and begins searching newspaper archives for missing persons cases, hoping to assume a fresh identity. She comes across the story of Carol Burden, a young girl who was kidnapped seventeen years earlier, and the trail begins to feel personal.
Meanwhile, Bob is fired from his management position after employees protest his treatment of Peggy. He spots Peggy's photo in the newspaper and becomes determined to prove that she is alive. Using clues gleaned from the Carol Burden article, Peggy drops hints to Durstin that suggest she is, in fact, the missing Carol. The two meet with Carol's father, Cornelius Burden, who is at first suspicious but agrees to let Peggy move into his mansion long enough to test the claim. After Peggy meets Carol's childhood nanny, Baba, and answers a series of questions, Cornelius grows more convinced that she could be his daughter.
Bob—having read about Cornelius's supposed reunion with "Carol" in the press—slips into the Burden mansion but is quickly incapacitated by Jimmy, the family’s loyal, watchful bodyguard. He later tracks Peggy to a local concert and follows her to a cafe, though Peggy manages to elude him. Bob does slip away with Peggy’s fingerprint from a plant vase, a detail that will become crucial later. The intrigue intensifies when Bob sneaks into the Burdens’ coming-out party for Carol, catching Peggy on the dance floor by surprise and presenting Cornelius with a forged marriage certificate bearing Peggy’s fingerprint, claiming the couple has long suffered amnesia and is married.
Peggy refuses to be defined by Bob’s deception and persuades Cornelius to let her return to Hotchkiss Falls to decide her own fate. Despite Bob’s relentless pressure, Peggy remains steadfast in her impersonation, and en route sabotages his car at a late-night diner. The pair end up spending a night in a motel, where Peggy presses Bob to join her in bed; his growing belief that she is truly Carol signals a turning point—Peggy would never have trusted him so completely, yet his doubt begins to waver.
Bob phones Cornelius to arrange Peggy’s removal from the motel, but before Cornelius arrives, Peggy confesses her deception. She is initially angry, but quickly tries to regain her composure. When Cornelius and Baba finally arrive, Bob attempts to block Peggy from exposing the truth, unaware that Cornelius has already received proof that Peggy is not his daughter. Yet, in a surprising turn, both Cornelius and Baba choose to embrace Peggy as Carol, having grown to love her for who she is rather than who she was supposed to be.
In the tender, unexpected denouement, Bob proposes to Peggy, while Cornelius looks forward to the prospect of a deeper fatherly bond. The story closes on a note of complicated, unresolved devotion: love, identity, and the power of chosen family weave together as Peggy navigates the blurred lines between memory, deception, and belonging, leaving the audience with a hopeful sense that the bonds she has formed—and the truth she has earned—are strong enough to withstand the truth about origins.
