Cast & Crew
Stewart Cole, secretary to retired millionaire Alan Rogers, appeals to amateur sleuth and mystery writer Ellery Queen to investigate the hold that two sinister men have over his employer. After accepting the case, Ellery drives out to Rogers' lakeside estate to search the room occupied by Bates and Corday, Rogers' former partners in the pearl business. Among their belongings, Ellery finds a newspaper clipping inquiring as to the whereabouts of Rogers' long-lost daughters, Margo and Marie, and realizes that Bates and Corday traced Rogers through the ad. That afternoon, as Nikki Porter, Ellery's secretary, leaves his office, she bumps into Marie Dubois, who is looking for Rogers, a former tenant in the building. After Nikki blurts out that Ellery is conducting an investigation at the Rogers house, Marie confides that Rogers is her father, but she has not seen him since she was a girl in Tahiti. Marie then shows Nikki the newspaper ad and documentation proving her paternity, along with a letter from Rogers' attorney, Lester Young, denouncing her as an impostor. Surmising that Rogers is ignorant of Marie's plight, Nikki volunteers to investigate the situation. That night, as Nikki eavesdrops outside a door at the Rogers' estate, she is discovered by Deborah, the housekeeper. Claiming to be Marie, Nikki presents the missing girl's documentation, thus dumbfounding Ellery. Accepting Nikki as his daughter, Rogers insists that she stay at the house and introduces her to his other daughter Margo, with whom he has been recently reunited. Later that night, Bates and Corday demand the money that Rogers cheated them out of when they were partners, and he agrees to pay them the next afternoon. After Nikki retires to her room, Ellery sneaks in and promises to return with the real Marie the next day. Overhearing their conversation, the housekeeper becomes suspicious and phones the hotel in which Nikki claims she is registered. The next morning, Ellery notifies Nikki that Marie is missing, thus forcing her to continue the masquerade. Rogers then insists that she accompany him to his lawyer's office so that he can transfer his estate to her and Margo. At the office, Nikki shows Young the letter denouncing her as an impostor, but he claims he never wrote it. After she leaves, Rogers confides that he believes the letter to be the work of Corday and Bates, and after withdrawing the cash from his account, he goes to pay them off at a waterfront bar. Ellery, meanwhile, turns to his father, Inspector Queen, for help in locating Marie. While Ellery is at the police station, the inspector is summoned to investigate a murder, and at the scene of the crime, they find the bodies of Bates and Corday. When the sailor who discovered the bodies testifies that the two were expecting a large sum of money that afternoon, Ellery deduces that the killer saw them counting the money and slipped in through the window to murder them. When Ellery notifies Rogers of the murders, Nikki panics and climbs into a canoe to flee the house. As she paddles out into the lake, a motorboat deliberately collides with her craft, sending it to the bottom of the lake. Back at the house, as Ellery questions Young about his activities at the time of the murder, Nikki returns, having pulled herself from the lake, and informs Ellery that someone tried to kill her. Afterward, Young asks Nikki to sign papers swearing that she is Rogers' daughter, and when she refuses, he accuses her of being an impostor and insists upon examining her belongings. To Nikki's surpise, the labels on the clothes in her suitcase verify that they were made in Tahiti, and Young apologizes. Later, Ellery explains to the surprised Nikki that the clothes were planted in her room, leading him to believe that someone is trying to protect her while someone else is trying to destroy her. When the inspector comes to question Rogers later that night, the butler runs out of the house and is stopped by Ellery. Under interrogation, the butler admits that he ran away because he found a gun and a pile of cash in Rogers' desk drawer and didn't want to testify against his employer. Rogers is then discovered poisoned in his bed, and Ellery suspects that the murderer substituted poison for the pills that the diabetic Rogers took nightly. Just then, the real Marie descends the staircase and greets everyone. Up in Nikki's room, meanwhile, the housekeeper explains that she was harboring Marie the entire time because she suspected that Nikki was a fraud. When the housekeeper produces a photograph of Margo, proving that she is also an impostor, Nikki shows it to Ellery, who accuses Margo of plotting with an accomplice to kill Rogers and then frame Corday and Bates for the murder. Once Rogers paid off his blackmailers, however, the plot was derailed, causing Margo to kill Bates and Corday and plant the money in Rogers desk, thus framing him for their murder and insuring his timely execution so that she could inherit the estate. Becoming impatient for the inheritance, Margo's partner then killed Rogers. As the inspector and Ellery question Margo in the study, the lights go off and a shot rings out. After tackling the assailant, Ellery turns on the lights and discovers that he has captured Cole. When the secretary's gun matches the weapon that killed Bates and Corday, Ellery declares that Cole and Margo were partners in crime.
Although a Hollywood Reporter production chart places J. C. Nugent in the cast, his appearance in the released film has not been confirmed. This was the first of three films in which William Gargan portrayed "Ellery Queen," replacing Ralph Bellamy in the series. For additional information on the series, please consult the Series Index and see the entry for Ellery Queen Master Detective in AFI Catalog of Feature Films, 1931-40; F3.1186.