[8] Johnny Drake, a sailor on shore leave in Santa Monica, meets a young woman named Mora in a local jazz club.

Mora tells Johnny that Captain Murdock is her godfather and he found her as an orphan living on the Greek island of Mykonos.

Johnny witnesses Mora being followed by a mysterious black-clad woman, the 'Sea Witch' whom she believes is one of the sirens, calling her to return to the sea to fulfill her destiny.

During a scuba dive on the day of the full moon, Mora cuts Johnny's air hose, apparently attempting to drown him.

Captain Murdock appears brandishing a gun, admitting to Johnny that he killed Mora's boyfriends because he could not bear the thought of her leaving him.

He planted the idea that she was a mermaid, incapable of living the life of a normal woman, in her head as a way of binding her to him forever.

When she matured and began to attract male attention, Murdock murdered the men she grew close to and let Mora think that she had caused their deaths.

"[11] Kansa states that prior to filming the director had turned down an offer from the Mickey Cohen gang to finance the picture.

"They were very charming men but I had visions that if the film didn't do well I'd end up at the bottom of the LA river in a block of cement!

[15]The entry for the film in Horror: The Aurum Film Encyclopedia states "Clearly inspired by Cat People (1942), following Val Lewton's principles by having a vividly realistic setting (the tawdry pier and funfairs) and providing a rational explanation for most of the mystery (the girl's adoptive father planted the siren story in her mind), it is both clumsy and tentative and strikingly atmospheric.

More of a fantasy than a horror movie perhaps, the film does make darkly minatory use of its dream sequences (the mermaid nightmarishly metamorphosing into an octopus) and the recurrent motif of the mysterious woman in black whose appearances frighten the girl.

[17] A fan of the film, Nicolas Winding Refn purchased the negative from the director's estate and then produced a new 4K digital restoration that was released in 2020.