For those not yet inaugurated into the oeuvre of influential B-movie producer Val Lewton, the Criterion Channel has you covered. The most famous of Lewton’s films is the Jacques Tourneur-directed Cat People, starring Simone Simon as a haunted young woman who may or may not turn into a leopard when impassioned. Lewton’s films blur the lines between the supernatural and the psychological, acting as much as investigations of why human beings believe in superstition and mythology as in the superstitions themselves. Isle of the Dead draws on the same themes as Cat People, this time as death and illness spreads across a Greek island in the aftermath of civil war.

Boris Karloff is General Nikolas Pherides, a Greek general during the Balkan Wars of 1912. While the troops bury the dead quickly to staunch the spread of plague, Pherides and Oliver Davis (Marc Cramer), an American reporter, travel to a cemetery island to pay their respects to the general’s deceased wife. There they find a small community living in the only house, including Albrecht (Jason Robards, Sr.), a Swiss archaeologist; his Greek housekeeper Madame Kyra (Helene Thimig); St. Aubyn (Alan Napier), a British diplomat, and his sickly wife (Katherine Emery); and Thea (Ellen Drew), the wife’s Greek caregiver. When one of the party dies during the night, Pherides summons his troop doctor to discover the reason. The doctor confirms the presence of plague, and orders that everyone remain quarantined on the island until the wind changes. As the group attempts to pass the time, they face the closeness of death, the inadequacy of medical knowledge, and scientific fact and superstition that combine to create a terrifying climax.

There’s no clear villain or monster in Isle of the Dead; rather, fear and developing paranoia drive the narrative, transforming the people on the island as they cope with their nearness to death and the causes of it. They each take refuge in medical knowledge and rationality, religion, superstition, or a combination of all three, questioning what they know and what they believe. It’s a remarkably subdued and philosophic horror film (which is no surprise to anyone who has seen other Lewton-produced narratives of terror), as the characters debate religion and science, superstition and belief systems. The crux is the “vorvolaka,” a vampiric figure whom the Greek housekeeper is convinced has manifested itself in Thea, given Mrs. St. Aubyn’s sickliness and Thea’s ruddy good health. But more interesting is the way in which the film plays with this theme, not as a supernatural threat, but as one embedded in the human psyche as the characters seek to find explanation and reason behind apparently meaningless death. Thea’s own superstitions begin to meld with her medical knowledge, and Mrs. St. Aubyn assures Thea that she’s no vorvolaka, but is herself irrationally terrified of premature burial.

Karloff in particular treads the line between sympathetic and villainous, as Pherides’s strictly rational world gives way to irrational concepts amid the terror of death. Because he’s so known for playing monsters and ghouls, it’s easy to forget what a fine actor Karloff is, how he can manifest both malevolence and gentleness in the same moment. He utilizes both here, at once likable and hard-nosed as a soldier, but truly caring, and then gradually paranoid and delusional as more people succumb to the plague.

Isle of the Dead bears the same stamp as Cat People, The Seventh Victim, and I Walked with a Zombie, the setting of the supernatural amid “exotic” surroundings that investigates the narrow divide between the truly supernatural and human psychology. Director Mark Robson was behind four of Lewton’s films, making him more prolific in the producer’s oeuvre than the more famous Jacques Tourneur. Here he employs chiaroscuro and nightmarish images in a tense, shadow-laden narrative that fully inhabits its characters’ psyches, lending terror to canopies of trees and dark hallways. What we fear, and why we fear it, lurks around each corner, and terror cannot be blown away by the sirocco winds.