At nine o'clock one evening, a man leaves the office of the Garfield Investment Company and, seeing the night watchman, asks for a match and the time before leaving the building. The watchman, Luigi Bacigalupi, knowing that no one should be in the building, investigates and finds Mr. Garfield lying dead in his office. Garfield is the fourth stockbroker to be strangled recently by an assailant who, in each case, has asked someone for a match and the time. Luigi identifies wealthy philanthropist Jerome Breen, a deaf mute who moved to the town two years earlier, as the man who spoke with him the night of the murder. Breen is acquitted, however, after his defense attorney leads Luigi to confess that he had been drinking gin the night of the murder, and court physicians determine that Breen has paralysis of his vocal cords and aural nerves and has been a deaf mute since birth. Newspaper reporter Jack Burton of the Chronicle believes Breen to be guilty. He is extremely worried when society reporter Jerry Crane, who has refused Jack's many proposals that they marry and raise chickens, is going to visit Breen to do a series of articles about him. Through his interpreter Jenks and by writing on a note pad, Breen, who is attracted to Jerry, charms her. After the Chronicle offers $5,000 for information regarding Garfield's death, Dave Werner, a stockbroker's clerk who came to see Breen during one of his interviews with Jerry, tells Jack that a meeting he plans to have with a certain person that night will determine whether or not he will give the reporter the story. Breen visits Werner that evening and, on his way out, asks Werner's mother for the correct time. She faints and Werner is found strangled. Police inspector James Riley and Jack accuse Breen of murder, but through Jenks, Breen warns that his arrest will only make the police department into laughing stocks. To test whether Breen can hear, Riley fires a shot out the door, but Breen shows no response. However, when Jack touches the piano keys, Riley notices Breen react. Outside, Riley tells Jack that he has an idea about Breen, which he wants to sleep on. After Jenks warns Breen that he may spoil their "swell racket" on account of "a skirt," Breen hits the last key on the piano, and a panel in one of the walls opens to a room, which he enters. The next day, Jack learns that Riley was found strangled in his bed. Afraid that Jerry may discover Breen's secret and then be murdered like Riley and Werner, Jack warns her to stay away, but she indignantly states that she plans to have dinner with Breen that night. The new inspector, Terrence Hogan, the foil of Jack's earlier razzing, assigns two officers to watch Breen's house with Jack that night. Jenks notices them in the bushes and interrupts Breen, who has just kissed Jerry's hand and put his arm around her. Jerry plays scales on the piano, and the panel opens, revealing a man who looks exactly like Breen. Jerry screams, but when Jack and the officers arrive, she is nowhere to be found. Hogan arrives and during his interrogation, drops a cigar ash on the piano keys. When he wipes it off, the panel opens, and the police shoot Breen's double. Jerry is rescued and Jenks escapes. Breen then speaks and reveals that he had formed a stock pool with the four dead brokers, but when they did not like the way he did business and threatened to go to the district attorney, he killed them and made sure that someone heard him speak so that when his brother, in his place, was found to be a deaf-mute, he could not be convicted. Werner, he says, tried to double-cross him, and Riley noticed his reaction to the piano. When Breen, who also admits having killed people in other cities, is handcuffed, he pricks his finger with a medieval poison ring and dies instantly. Jerry then admits that she has been stupid and accepts Jack's proposal.