American James Nevill, president of Amalgamated Industries in London, is horrified to discover that eccentric professor Cyrus McGowan no longer plans to purchase the huge cache of supplies that Jim has procured for him. Realizing that he and his company will now be financially ruined, Jim stoically asks his board members for forty-eight hours to present a new plan. Although no one knows that Jim is in trouble, his secretary, Joan Peterson, who secretly loves him, recognizes that something is amiss. That night, while Jim's beloved wife Andrea throws a party, Jim invites his old friend, Paul Kirby, into his office. There, Jim berates Paul for having stolen money from him in the past and gambling it away. Then, explaining that he wants to secure Andrea's future with a large insurance payment, Jim orders Paul to murder him within five days. Paul refuses, but is forced to agree when Jim threatens to expose an earlier murder Paul committed. By the end of the party, Paul is so drunk that Jim asks board member and family friend Peter Glanville to escort him home, and when Paul insists on stopping at the bar where his girl friend, Eileen, works, Peter subsequently overhears him reveal Jim's scheme to her. Over the next few days, Jim travels to Dublin to give Paul time to gather his courage. The afternoon he returns, McGowan bursts into his office and announces that their deal is on once again. Overjoyed, Jim instructs Joan to tell Paul that their arrangement is cancelled, but Joan cannot locate Paul. At home that night, Jim manages to soothe Andrea, who is furious with him for leaving town so suddenly. Desperate to find Paul, Jim asks Peter to watch after Andrea, and races to Paul's apartment, where he is shot at. By the time he revives, Joan has tracked him there and insists that he tell her the truth. Over the next four days, Joan hires a private detective to track down Paul, and soon receives a message asking Jim to meet Paul at an apartment building. When Jim goes there, however, he is chased through the streets by an unknown assailant in a car. He visits Eileen, but she tells him that Paul has fled the country and shows him a letter Paul wrote to her from abroad. In the office the next day, a bomb hidden in Jim's desk detonates, but no one is harmed. Now knowing that the killer is not Paul but has access to his office, Jim suspects his nemesis, board member Heisen. Although Heisen admits that he loathes Jim for his often questionable business tactics, he presents a secure alibi. The next day, Jim, now desperate and exhausted, finally reveals everything to Andrea, and they ponder who could have shot at him in Paul's apartment. Andrea suddenly realizes that Peter did not attend the theater with her that evening, but instead went home early. They return to the house and invite Peter over. As Jim waits in the dark, he hears Andrea scream outside and rushes to the greenhouse, where he finds Peter holding a gun to Paul's back. After Peter reveals that he and Andrea learned of Jim's plan to have himself killed, and decided to kill him themselves to gain the insurance money, Andrea appears in the doorway and confirms Peter's claims. Peter orders Paul to shoot Jim and then himself, to make the act appear to be a murder-suicide, but just then Joan arrives and calls out for Jim. Paul grabs Peter's gun and it goes off several times, killing Andrea. Jim tries to strangle Peter but finally stops when Joan screams that she loves him. While Paul holds his gun on Peter until the police arrive, Joan sadly watches a heartbroken Jim carry Andrea's dead body into the house.