Jim Kennedy accidentally kills Duncan Channing, his secretary, during a game of charades because someone replaced the blanks in his gun with bullets. Then Kennedy is killed in a way that makes his death seem like a suicide. Just before he was killed, Kennedy had left a letter telling of a previous attempt on his life and his suspicions as to the identity of the murderer. Lawrence, the butler, reveals that he heard Kennedy quarrel with Channing before his murder. Colton, Kennedy's lawyer, also quarreled with him because Colton did not approve of his new will, which disinherited Esme, Kennedy's wife. Walter Grayson, Esme's brother, tells the police that he was in the cardroom all evening, but Millie Scripps, the Kennedy maid, reports that when she knocked on the door, Grayson did not answer. After informing Inspector Taylor that she has something to tell him, Millie is killed. Taylor wants to arrest Grayson because Millie attempted to blackmail him into marrying her. Sometime later, Lawrence telephones Taylor to announce that he has found the missing will and Kennedy's letter, but before he can reveal where he has hidden the evidence, he is killed by a needle discharged from the phone receiver. Julia, Kennedy's aunt, finds the will and the letter hidden in the vacuum cleaner. She takes them to criminologist Phillip Montrose, but when the letter reveals that Montrose is Esme's lover and the murderer, he commits suicide by jiggling the phone hook, sending a needle to his brain, and dies just as Lawrence did.