After a fight with his wife, Scott Henderson picks up a mysterious woman in a bar and they go out. The woman refuses to exchange names, becoming the phantom lady of the film. When Henderson returns home, he finds cops waiting to question him because his wife has been murdered with his necktie. Henderson and the cops try to find the phantom lady who can provide him with an alibi but fail. It's up to Carol, Henderson's loyal and secretary with a secret to trace the phantom and set Henderson free.