Lawyer Oliver Keith (Reginald Denny) in love with his secretary Ella Carey (Patricia Farr), but refuses to do anything about it during office hours. Thus, it's up to Ella to ardently pursue Oliver in her spare time. Their romance is temporarily shelved when Oliver and Ella combine forces to solve two seemingly unrelated murders. Lady in Scarlet is yet another spin on the Thin Man formula, this time from low-budget Invincible Pictures. No one expressed much enthusiasm over the film, though Reginald Denny garnered some of his best reviews in years.