A lost soldier discovers a mysterious beauty haunting a half-deserted castle.

André Duvalier, an officer of Napoleon's army, is lost somewhere on the Baltic coast and collapses from exhaustion only to be awakened by a mysterious girl who then disappears into the sea. Later, he wakes in a strange hovel, attended by an old woman and her half-witted servant, Gustaf. After he sees the girl again in the forest, she vanishes and André is told by Gustaf that she can be found in the castle of Baron von Leppe. Upon his arrival there, he recognizes the elusive girl's likeness in a painting which the Baron insists is a portrait of his long dead wife. After von Leppe requests him to leave, Duvalier discovers the dying Gustaf who urges him to return to the castle and find the girl. When he does so, she agrees to leave the evil place with him, but again she mysteriously disappears. The Baron's servant, Stefan, reveals that the old woman's son, Erik, thought to be dead for 20 years, is in fact alive, having killed the Baron and taken his place. As André rescues the girl, she becomes a mouldering, decayed corpse in his arms as the crazed Erik drowns himself.