Isle of the Dead (1945) directed by Mark Robson
During the Balkan War of 1912, a harsh Greek general (Boris Karloff) goes to visit his wife's grave on an island near his latest successful battle. The grave has been plundered and her body is gone, so the general visits the locals to demand an answer. Only a handful of people are left on the island, a few caretakers and some tourists who fled from the battle to the island. The general is convinced to spend the night. Someone falls victim to septicemic plague. The general enforces a quarantine to protect his troops, even though a diplomat wants to get back to his duties and some young lovers want to escape. If that wasn't trouble enough, an old lady spreads superstition, claiming the female young lover is a Vorvolaka, a mythical creature that drains the life force of its victims. At first the general is very rationalistic and gets a military doctor to come. When the doctor falls to the plague, superstition rears its ugly head.
The movie is produced by Val Lewton (of Cat People and I Walked with a Zombie fame) and exemplifies his "less is more" style. Sound effects and shadows create the atmosphere of terror. The tension between superstition and science is well drawn, shifting sympathy from character to character throughout. The ending isn't fully satisfying but still delivers some chilling moments and sympathy for all the characters, even the misguided ones.
Recommended for atmospheric horror fans and Karloff fans (if you aren't a Karloff fan, what's wrong with you?).
The movie is available as a horror double-feature in the Val Lewton collection along with Bedlam, which I haven't watched yet but will soon!