On a quiet street, an old homeless woman is murdered after seeing a light through the basement window of the abandoned 11 Crescent Drive. From his window at number 10, Barnaby Fielding, Richard Lyon, witnesses the crime.
Elizabeth Howard, Gail Russell, arrives as the children's governess to Barnaby and Ellen, but she is met with resistance from the boy, who is unusually attached to their former governess, Maxine, and blurts out, "You're my enemy! I hate you!" Elizabeth’s room overlooks the eerie garden next door, and she soon notices a watch that belonged to the murdered old woman on her dressing table, tying the two houses together in a thread of unease.
Over the following weeks, Marian Tygarth, [Isobel Elsom], a widow who owns the shuttered 11 Crescent Drive, returns to put the house up for sale, and Elizabeth begins to suspect that someone is slipping into the cellars. She turns to David Fielding, [Joel McCrea], the children’s father, but he dismisses her concerns, brushing aside the creeping tension that she feels. Hoping for counsel, she confides in Dr. Charles Evans, [Herbert Marshall], a neighbor and friend, who warns her not to involve the police because David would not approve (unknown to Ellen, David was once suspected of murdering his wife). Ellen reveals to Elizabeth that Barnaby is the one who lets the lurking man into the house at night, acting on Maxine’s orders, deepening the sense of danger in the home.
Desperate for help, Elizabeth learns from the employment agency that no one can be sent that day, and a new maid arrives. Elizabeth soon realizes the new hire is Maxine, [Phyllis Brooks], the very person Barnaby claimed to be protecting, and David tries to eject Maxine from the premises. Shortly after, Maxine is found murdered outside the empty house, and David is nowhere to be found, casting him as the prime suspect in the eyes of the police.
After the police depart, Mrs. Tygarth visits Elizabeth to keep her company after the children go to bed. She confides that the man who murdered her husband is next door and that she has been forced to help him clean up the crime scene from twelve years before. She intends to call the police, but instead goes next door with a fatal plan, only to be killed by the unknown man. Elizabeth remains unsettled and searches for answers, ultimately turning to Dr. Evans for help. When David arrives, he confronts Evans, who is revealed to be the killer—an escalation of motives rooted in a long-buried fixation on Mrs. Tygarth. In the final tense moments, the truth about Dr. Evans’s obsession comes to light, and the mystery of Crescent Drive edges toward its chilling conclusion.
