Doing a favor for an old friend gets Kent Murdock involved in a murder
Newspaper photographer Kent Murdock goes to Union City for the sake of Helen Farnsley, an old friend whose marriage is in trouble. Long ago he warned her against marrying Lee, and now that their life together has turned sour he wants to help her escape it. But the trouble in Union City starts as soon as he gets to his hotel room.

Behind the mirror, Murdock finds a diamond bracelet belonging to the room’s previous resident, a talent agent named Harry who returns a few minutes later to collect it. That night, Murdock sits down with Helen’s husband, who asks for a few hours alone in the room to think. When Murdock returns, Lee has been murdered, and the police are looking for the room’s owner. Kent doesn’t stop to talk to the cops. It would be much easier to find the killer himself.