Scott
Henderson (Alan Curtis) picks up a grave, mysterious woman in a bar. She
agrees to go to the theatre with him on the condition that they not
exchange names. When Henderson returns home, he finds three cops waiting
for him. They accuse him of strangling his wife to death with his own
necktie, but he claims that the phantom lady can clear his name.
Accompanied by the cops, Henderson interviews the barman, the taxi driver
and the singer who had all seen him the previous night with the phantom
lady, but they deny seeing her and his alibi is unproven. Henderson is
tried for the murder of his wife and sentenced to death.
His assistant
Carol (Ella Raines), who is secretly in love with him, follows the trail
of the phantom lady. Aided by Inspector Burgess, who had put Henderson
away and then changed his mind, she begins to question the witnesses. She
surveills the barman, follows him home and questions him. Desperate to
get away, the barman runs in front of a car and is killed. Carol then
dresses in a tight dress and sets out to seduce Cliff Millburn (Elisha
Cook Jr.), the drummer at the theatre who had seen Henderson with the
phantom lady. Cliff tells her he was paid $500 to lie about seeing
Henderson and the lady, but then finds out that Carol is investigating
him. He tries to catch her but she runs out of her apartment building.
Meanwhile, the man who had bribed Cliff to lie strangles Cliff.
Henderson's
best friend Jack Marlowe (Franchot Tone) returns from South America to
help Carol and Inspector Burgess in the investigation. However, he is the
killer himself. By surveilling the singer, Carol finds out that the
singer's hat and the phantom lady's hat are made at the same place and so
trace the phantom lady. Marlowe and Carol visit the phantom lady, Ann
Terry, who can clear Henderson. Ann has had a nervous breakdown following
the sudden death of her fiance the previous year, making her an unreliable
witness, but Carol takes her hat as evidence. Marlowe pretends to call
Inspector Burgess and tell Burgess to meet them at Marlowe's apartment. At
Marlowe's apartment, Carol finds incriminating evidence. Marlowe confesses
that he killed Mrs. Henderson because they had been having an affair and
she wouldn't run away with him. He prepares to strangle Carol, only she is
saved by the buzzer. Inspector Burgess rushes in (how did he know to go
to Marlowe's?) and Marlowe commits suicide.
Carol returns to being Henderson's assistant and he leaves a dictaphone recording telling her she will be his dinner date from then on. She clasps the dictaphone recorder to her chest and looks ecstatic.