In 1870s France, a string of strange murders occur on the Rue Morgue, a fictional street in Paris. The authorities are baffled, but they do know of one man who may have the answers - a professor named Dupin (Steve Forrest). Dupin agrees to help the police. Soon a list of suspects is established. The roster includes a one-eyed sailor named Jacques (Anthony Caruso). But there is also Professor Marais (Karl Malden), who is involved in bizarre and unauthorized animal experiments.