The 1961 movie Night Tide is a psychological thriller, with elements of fantasy, horror and dread thrown in there. The story is about a young sailor named Johnny Drake (Dennis Hopper) who falls for a mysterious woman named Mora (Linda Lawson) who works as a fake "mermaid" in a carnival attraction on the beach. Johnny is immediately enthralled with Mora when he first sees her in a night club, and despite her initial disinterest, she allows him into her life and they start a romance.
Howeber, this romance isn't a straightforward one, because there is something unusual about Mora. Her previous boyfriends died mysteriously, and Mora believes this is because she is an actual mermaid, or a siren, who lures men to their deaths. She was found as a child on an island by a man named Murdock, who raised her and owns the carnival attraction she works at, so she knows almost nothing about her true history. Yet she feels that the sea is calling to her, and fears that she will one day turn on Johnny against her own will.
This film is dreamlike in its quality and Linda Lawson gives a mesmerizing performance as the mysterious Mora, who vacillates between being the victim and the villain of the story. Aside from the brief scene of Mora performing at the carnival attraction, there a few dreamlike scenes of Mora with a mermaid's tail, though it's never made clear whether these are real or merely in the imaginination, just as it's never made clear whether Mora really is a mermaid or not. Thus the film leaves it to the viewer to decide which version they like best.