When a man is found murdered in a fashionable Fifth Avenue apartment, stabbed in the back, the witnesses are convinced about a woman they saw leaving his apartment. However, the woman has a twin sister, and both of them have alibis for the night of the murder. Finding out which one is the killer seems impossible, but the detective on the case is very determined...

Olivia De Havilland recreates her original duel role in the movie, as she plays the twin parts of Ruth and Terry.