December 1945. An unconscious woman is pulled from the river north of Samaria, Louisiana. After several days of medical treatment under Dr. Justin Charles she regains her strength, but it's apparent she suffers from amnesia. During her convalescence, the stranger sketches out a piano on a drawing pad. Charles has a piano delivered hoping it can trigger memories locked in her mind.
Surprisingly she plays beautifully and the music casts a spell over the town, leading to a series of unusual and tragic events - both healings and deaths. When two survivors of German war atrocities recognize her, Charles's suspicion is heightened concerning her mysterious appearance. Dr. Robert McGinty, a psychologist treating soldiers returning from the war, assists Charles with the treatment of the stranger attempting to restore her memory. What they unknowingly expose is the full power of evil.