Attorney Anthony Keane agrees to represent Londonite Mrs. Paradine, who has been fingered in her husband's murder. From the start, the married lawyer is drawn to the enigmatic beauty, and he begins to cast about for a way to exonerate his client. Keane puts the Paradine household servant on the stand, suggesting he is the killer. But Keane soon loses his way in the courtroom, and his half-baked plan sets off a stunning chain of events.