The mad Dr. Caligari, with the help of a somnambulist named Cesare, spreads fear and terror around a small North German town. During the day Caligari presents Cesare, who suffers from a strange trance-like illness at the fair. There the tall, skinny and pale somnambulist predicts the future to onlookers. But at night Caligari’s slave creeps through the city and commits terrible murders under the influence of his master. When one night a young man is murdered, to whom Cesare had prophesied his nearing death, Francis, a friend of the dead man, suspects that Dr. Caligari is involved. When Francis' friend Jane is threatened and kidnapped by Cesare, suspicion becomes certainty.
The film helped German cinema gain international esteem and was also a national style-setter.