Returning home through a bog late one night, sixteen-year-old Dick Dodds passes a trail that for some reason sends a chill up his spine. He feels the same inexplicable terror the next day when he explores the trail further and meets a girl, Helen Johnson, who saw something that looked like a man with no arms or legs moving and gliding across the landscape. The mystery deepens when a local widow, Mrs Knowles, becomes convinced that something evil...