London: two detectives secure the arrest and conviction of a criminal. Later, Frank Webber, one of the detectives, visits a tea house with girlfriend Alice White. The couple argue, and Alice leaves instead with an artist, who she has secretly agreed to meet.

Alice goes back to the artist's flat, where she flirts with him. He persuades her to try on a dress, but while she is changing he steals her own dress. The artist assaults her, but she grabs a bread knife and stabs him to death.

Doing her best to conceal any evidence of her presence in the flat, Alice returns home. However she has failed to notice a glove left at the crime scene, and this is found the next day by Frank, who has been assigned to the case.

Frank visits Alice at her father's shop, but the two are disturbed by Tracey, a petty criminal who saw Alice at the dead man's flat, and uses his knowledge to try to blackmail the couple. Tracey, however, has himself been witnessed at the flat, and finds himself the chief suspect. With the police in pursuit, Tracey is forced to flee, and is killed trying to escape on the roof of the British Museum.

Alice, determined to confess her guilt, visits Scotland Yard, but her attempt to talk to the Chief Inspector is prevented by Frank, who escorts her out.