To the melancholy island of Guadalupe come a band of refugees, stripped of their friends and their country by the war. Among them dwells a brooding, sinister man known only as "El Hombre," whose memory was destroyed by the brutality of the Nazis. One evening, as El Hombre sits trance-like at the piano and plays a somber melody, his music drifts into the room inhabited by other refugees, Dr. Hoffman, his wife Anna, and their invalid charge, Marya Volny. El Hombre's playing reminds Anna of Jan Volny, a famous pianist from her homeland of Czechoslovakia, and she bitterly reflects upon the life that they lost. After finishing the piece, El Hombre reads a notice from the governor, warning of the refugees about "murder boats" that will promise them asylum in the U.S., but will leave them to perish at sea after fleecing them of their savings. The demented El Hombre takes the warning as a sign to destroy the fishing boat owned by his compassionate employer Angelo. El Hombre's act infuriates Angelo's cruel brothers, Luigi and Marco, who loath the stranger and wish him dead. As Marya's condition worsens, Anna blames herself for forcing the girl to leave her homeland and recalls the conditions that drove them into exile: After invading Prague, the Nazis grant permission to Czech pianist Jan Volny to present a concert. They stipulate, however, that "The Moldau," a much-loved patriotic symphony written by Bedrich Smetana, be excluded from the concert. Carried away by the beauty of the music, Volny ends his concert with a four-minute paraphrase of the famed symphony. Realizing that his act will draw the wrath of the Nazis and that his wife, Marya, will also suffer at the hands of their oppressors, Volny arranges for the Hoffmans to smuggle her out of the country, but before he can escape himself, he is captured and subjected to unspeakable violence, which deranges him. Enroute to a concentration camp, Volny overpowers his guards and escapes. After making his way to Lisbon, he hides on a fishing boat owned by Angelo and his brothers, which embarks shortly thereafter and carries him to the island of Guadalupe. In the fog of his unhinged brain, Volny fails to remember his own name and identity, and is thus dubbed El Hombre. As Anna's thoughts return to the present, Marya, enchanted by the sound of El Hombre's piano, rises from her bed, inches her way down the stairs and then collapses in the street. El Hombre finds her there, and as he fingers the crucifix encircling her neck, his memory begins to return. When the Hoffmans come looking for Marya, El Hombre retreats into the shadows. Later, he begins to recall snatches of his life with Marya, but his reverie is cruelly interrupted by Luigi's harsh voice challenging him. Moments later, from the street, Angelo hears gunshots, and hurrying to their source, he finds Luigi, gun in hand, standing over El Hombre's body. As the brothers argue, Luigi stabs Angelo with an ice pick. Noticing that El Hombre has vanished, the wounded Angelo follows a trail of blood into the street and up the stairs to Marya's room, where the Hoffmans are notifying the police of Marya's death. At her bedside, El Hombre cradles Marya's lifeless body in his arms, begging her to return to life. His entreaties echo the words spoken to him by Marya at the time of their separation in Czechoslovakia, affirming her certainty that he will one day come for her.