The Dark Mirror stars Olivia de Havilland as twins Ruth and Terry Collins. A man is murdered and the woman suspected is Ruth. However, thanks to some complex legal wrangling, neither she nor her twin sister Terry can be convicted of the crime because no one knows which of them did it. Lieutenant Stevenson (Thomas Mitchell) is determined to solve the case and asks psychiatrist Dr. Scott Elliot (Lew Ayres) to work out whodunnit.
My Olivia de Havilland education is sadly lacking with The Dark Mirror only my third film of hers (see reviews of Government Girl (1943) here and The Private Lives of Elizabeth and Essex (1939) here). However, it's not as though I'm unaware of her excellence and maybe her centenary year is the right time to delve further into her career. Certainly, she is the reason why The Dark Mirror is so interesting. The psychological discussions seem a little dated now but the nuances of character that de Havilland brings to both women are excellent. She plays a nice woman and an evil one with such subtlety that, even when you're clued in on what's going on, it's a thoroughly enjoyable spectacle. It's not difficult to see how the special effects of de Havilland playing both parts was managed but it doesn't have to be complex, it just has to work, and it does. If you didn't know there was only one actress involved, I doubt you'd be able to guess.
It's an atmospheric film and I'll admit I was getting nervous the closer I got to the end. There's a twist that I was both expecting and hoping for and the reasoning behind the murder comes across as refreshingly human in the end. Ultimately, I was gripped by this one and my tiptoeing into the films of Olivia de Havilland is going well.