Bob Corey, who is recovering from a series of spinal operations at the Birmingham Veterans' Hospital in Van Nuys, California, is very worried about the disappearance of his friend, Steve Connolly, with whom he intends to run a ranch after he leaves the hospital. One night, a strange woman comes into Bob's room and informs him that Steve has been badly hurt. Bob, who has been drugged to help him sleep, groggily promises to join her in ten days, and she writes down her address. Later, however, Bob cannot find the address, and the doctor suggests that the woman was an hallucination. After Bob leaves the hospital, the police, who are investigating the murder of gambler Solly Blayne, question him about Steve, who is their main suspect. The police explain that on the night Blayne was killed, he quarreled with Steve at his hotel. After the murder, Steve disappeared and has not been seen since. Convinced that Steve is innocent, Bob tells the police about his mysterious visitor, and they promise to investigate. Bob then checks into Steve's hotel room, where Sybil, the maid, tells him that Steve and Blayne were fighting over $40,000 and shows him a business card from a mortuary in Glendale that Steve left behind in his room. The mortuary owner, Ben Arno, recognizes Bob from the Army and states that he encountered Steve at a boxing match and offered him a job, but Steve never pursued it. Later, Bob's nurse, Julie Benson, suggests that they question Solly's wife. Mrs. Blayne reports that the day Solly was killed, he told her he had won $40,000. After Solly was shot, she called Dr. Anstead, but it was too late to save her husband's life. Bob then examines Steve's phone bill and discovers that Steve placed a call to a woman named Bonnie Willis. At her house, he sees a photograph of his mysterious visitor and learns that her name is Lysa Radolph and that she has also disappeared. Bonnie, who like Lysa met Steve at the club where they both worked, then mentions a man named Lou Walsh, who is Lysa's lover. After Bob leaves, Bonnie is murdered with the same gun that killed Solly. Bob tells the police about Lysa and Walsh, but the police are unable to locate Walsh, nor can they find any pictures of the mysterious man. Then the police are summoned to the hospital, where a dying Chinese man named Quong has spoken of Steve. Quong tells the police and Bob that it was Walsh who owed Blayne $40,000. After Blayne's murder, Steve hid out at a house that Walsh owned under a different name. Quong overheard Lysa implicate Walsh in Solly's murder and convince Steve, with whom she has fallen in love, to go to the police. Quong then saw Walsh watching Lysa and Steve through the window of the house, and later, Walsh released the brakes on a car, crushing Steve. Before he can tell the police the location of Walsh's house, Quong dies. Julie then decides to search Dr. Anstead's office to see if he has a record of treating Steve. Anstead discovers her there and, after locking her in another room, calls Bob and gives him the address of Walsh's house, but before he can reveal any additional information, Walsh kills him. Unknown to Walsh, Julie has overheard the murder and knows Walsh's address. She attracts the attention of the janitor and calls the police. Meanwhile, Bob goes after Steve, and finds Arno waiting at the house. Admitting that he is Walsh, Arno explains that after Lysa returned from the hospital, she told him that she was leaving him, so he killed her. He threatens to kill Bob, but Steve, in a body cast, prevents the murder. When the police arrive, there is a shootout and Arno is killed. Steve is rushed to the hospital, and after he recovers, Julie and Bob, who have been married in the meantime, take him with them to the ranch.