Scotland Yard Detective Frank Webber (John Longden) escorts his girlfriend Alice White (Anny Ondra) to a tea house. They have an argument and Frank storms out. While reconsidering his action, he sees Alice leave with Mr. Crewe (Cyril Ritchard), an artist she had earlier agreed to meet.
Crewe persuades a reluctant Alice into coming up to see his studio. She admires a painting of a laughing clown, and uses his palette and brushes to paint a cartoonish drawing of a face; he adds a few strokes of a feminine figure, and they both sign the "work". He gives her a dancer's outfit and Crewe sings and plays "Miss Up-to-Date" on the piano.
Crewe steals a kiss, to Alice's disgust, but as she is changing and preparing to leave, he takes her dress from the changing area. He attempts to rape her; her cries for help are not heard on the street below. In desperation, Alice grabs a nearby bread knife and kills him. She angrily punches a hole in the painting of the clown, then leaves after attempting to remove any evidence of her presence in the flat, but accidentally leaves a glove. She walks the streets of London all night in a daze.
When the body is found, Frank is assigned to the case and finds Alice's glove. He also recognizes the dead man, but conceals this from his superior. Taking the glove, he goes to see Alice at her father's tobacco shop, but she is too distraught to speak.
As they hide from her father in a telephone booth, Tracy (Donald Calthrop), arrives. He had seen Alice go up to Crewe's flat, and he has one of her gloves. When he sees Frank with the other one, he attempts to blackmail them. His first demands are petty ones, and they accede. Frank learns by phone that Tracy is wanted for questioning: he was seen near the scene and has a criminal record. Frank sends for policemen and tells Tracy he will pay for the murder.
Alice is apprehensive, but still does not speak up. The tension mounts. When the police arrive, Tracy's nerve finally breaks and he flees. The chase leads to the British Museum, where he clambers onto the domed roof of the Reading Room and slips, crashing through a skylight, and falling to his death inside. The police assume he was the murderer.
Unaware of this, Alice feels compelled to give herself up and goes to see the Chief Inspector at New Scotland Yard. Before she can confess to him, the inspector receives a telephone call and asks Frank to deal with Alice. She finally tells Frank the truthâthat it was self-defense against an attack she cannot bear to speak ofâand they leave together. As they do, a policeman walks past, carrying the damaged painting of the laughing clown and the canvas where Alice painted over her name and Crewe's.
Who plays Tracy?
Donald Calthrop