A familiar film noir opening: a man lies dead in his luxury apartment, and a beautiful woman seen leaving the building is positively identified as the murderer. But...this beautiful woman has an identical twin, and police, at a loss to determine which sister is the murderous one, call on the services of a psychiatrist (Lew Ayres). Olivia de Havilland, aided by brilliant trick photography, is excellent as both twins--one charming and trusting, the other aggressive and paranoiac. The doppleganger motif is intriguingly worked into this film noir thriller of identification and misidentification, and the script, spiced with red herrings and suspenseful ambiguities, contrasts nicely with Siodmak's sharp, uncluttered visual style. The clincher, cleverly effected through mirrors set up to reveal the murderer, also reveals Siodmak's interest in the darker reaches of the mind.