Aside from his imposing height, Boris Karloff’s dark, sunken eyes are his best asset — as much able to be persuasively used by the man they’re attached to to telegraph a sinister inner life as a well-intentioned one. They’re put to great use in The Black Room, a Gothic horror movie in which he plays identical twins distinct in personality in the classic good-bad binary movies customarily prefer. 

Karloff’s third project of 1935 begins in late-18th-century Tyrol, moments after the births of two boys, Gregor and Anton (both of whom Karloff plays in adulthood), to a baronian clan. The occasion is less a cause for celebration than panic. There’s an old prophecy in the family that if twins ever appear in the bloodline, then it’s fated that the younger brother kills the older — who will, no matter what, inherit the family’s title and lands — specifically in a claustrophobic space in the family castle referred to as The Black Room.

Gregor and Anton’s kin decide to immediately build a wall over the cursed room; as the years pass, the prophecy seems less likely to come true. The brothers rarely see each other, with Gregor becoming a despotic ruler trailed by serial-killer rumors while Anton mostly uses the family funds to travel. Sadistic, solipsistic Anton is so despised around town that he cannot guarantee he won’t be shot at when he steps out in public or that a meal won’t be free of poison. Gregor’s time getting to know strangers has, in turn, made him the sort of empathetic and compassionate person that, when pitted against Anton’s nastiness, makes him seem almost saintly. 

Karloff plays neither sibling with the type of caricatured bigness that for other actors might be the obvious approach to better differentiate the roles. Anton’s wilted-smile sensitivity can be genuinely touching, and Gregor’s quiet slipperiness gives his transgressions mid-movie and onward an extra twinge of surprise, even if we’re well aware that we should know better. One of the film’s best moments finds Gregor practicing, in front of a mirror, how to impersonate his brother, correcting his slouch and attempting to will lightness into his eyes. It feels like something of a meta touch playing in reverse: a said-to-be-gentle actor adjusting his demeanor to better personify the villain role he’s been assigned.  

At 68 minutes, The Black Room doesn’t quite feel long enough; the eventual onslaught of twin-versus-twin scheming and murderous twists feels overcrowded after what had been a tight, gripping build-up. You also just want to stay in the film’s world a little longer — mostly set in a shadow-bathed castle patchily brightened by candlelight and fireplaces, it’s cozy in a dark-and-stormy-night way — and get some more time to relish in the presence of Karloff, who, though largely relegated in his career to the horror genre, never appeared to phone it in. But there’s no denying that even when you want more, two Boris Karloffs is better than one.