Night Tide retells the legend of the sailor and the mermaid. It is set in Venice - Venice California, a curiously decrepit suburb of Los Angeles, which sprawls along the waterfront, surrounded by oil-wells and Santa Monica. It is, in part, absurdly grand - miniature canals, without water but with footbridges arching over them - and quite run down. All of this is captured by Harrington's camera, and provides a splendid setting for a tale of mystery and suspense.

The plot concerns a young sailor who falls prey to a lonely attractive girl called Mora, who, in between solitary walks and visits to jazz cellars, is employed as a mermaid at an amusement park. Her employer is also her guardian - a retired and garrulous English sea captain, living in a large and somewhat mysterious house - who hastens to inform the young sailor of the girl's strangeness. The sailor hears this from all sides, and from the girl herself. She believes herself to be descended from an ancient race of sea people, the sirens of Greek legend who lured sailors to their destruction. Both of her previous boy friends, it is disclosed, were drowned in mysterious circumstances.