In Tirol in the late 19th century, when twins are born to the ruling Baron de Berghman, the youngest, Anton, is sent away due to a family legend that the youngest twin will kill the oldest. Two decades later, the elder twin, Gregor (Boris Karloff) arranges for Anton's (also Karloff) return so that the brothers may rule their country jointly. Upon Anton's arrival, mysterious disappearances and murders occur -- and when the local peasants accuse Gregor, he assumes his more popular twin's identity.