In the 1960s, former child star Shirley Temple had her own television show(s) where she got to play the leading role in a bunch of famous fairytales and folklore stories. Hans Christian Andersen is one of the stories she decided to tackle, making this one of the earliest live-action adaptations of the fairytale. It's a pretty ambitious for a 60s television show to try to tell The Little Mermaid, but the cheesy sets and costumes aside, this version is notable for not turning the dark-haired princess into a villain, which puts it in the minority.
The show opens with the prince on his ship, and the fateful storm where he almost drowns. Indeed, the little mermaid saves the prince even before the opening titles, which shows just how quickly into the action this version takes us.
The little mermaid seems to save the prince merely because she just happened to be there when he fell overboard, and takes him to shore and leaves. The prince is discovered and awoken by a dark-haired maiden who has devoted herself to some sacred temple and cannot mix around with men. The pair are immediately attracted to each other, but the maiden is quickly whisked off This version appears to be set in ancient Greece/Rome (they use names of Roman gods like Neptune, but refer to Thracia, which is part of ancient Greece, so, whichever) where the men like to wear colourful tights.
The little mermaid is all a-flutter, and quickly figures out that she has fallen in love. When she tells this revelation to her grandmother, she gets a supportive response, for it turns out that her grandmother once fell in love with a human as well (wait, WHAT) and knows first-hand how cruel men can be, for the man she fell in love with laughed at her when he saw her tail. (Boo, hiss!) This doesn't deter the little mermaid, and she happily tells her father, who laughs at her foolishness.
Grandmother soon realises that the little mermaid really wants to be with her prince, and reveals that there is a way to grow legs. The little mermaid meets Zuzu (spelling?), a manta ray who works as a go-between for the sea hag. He sets a remarkably cheap price on legs, i.e. gold coins off the eyes of dead sailors, and some really rare black pearls, which the little mermaid promises to get.
One thing this version of The Little Mermaid does is fit a trend where the sea witch is awesome. She's snarky and has the best delivery, filled with disdain and amusement on the little mermaid's predicament. She also rightly tells her minion Zuzu that he quoted far too low a price, but decides to be a good sport and advises the little mermaid to turn back while she still has the chance. That doesn't work, so she explains the conditions of the spell, which is that growing legs will be extremely painful, and she'll have a hundred sea tides to win the prince's love, or she'll turn into a speck of sea foam. The little mermaid is scared, but takes the potion and goes to dry land to grow some legs.
Up on land, the prince has been all moody and emo because of the mysterious dark-haired maiden he'll "never" see again. But then the little mermaid arrives, pulling him out his funk and cheering him up immediately. At first the little mermaid is overjoyed that they hit it off immediately, but then fifty sea tides pass and she realises that the prince only looks at her as a sisterly companion and nothing more. It seems that even with the advantage of keeping her voice, she's nowhere near winning her prince's heart.
More time passes, and the prince's father declares that the prince will have to marry the princess of a neighbouring kingdom for diplomatic reasons, and by coincidence their wedding will take place just before the 100th sea tide. This upsets the prince, who asks the little mermaid to comfort him, but she is far more upset as this turn seals her death.
As it turns out, the princess is the very same maiden that awoke the prince on the shore after he almost drowned. The two are ecstatic to see each other, and confess that their love is mutual and their happiness unlimited. This is a nice turn from other adaptations that make the dark-haired princess unworthy of the prince's love, and here the pair are very firmly the show's One True Pairing, professing their adoration for each other on and on and on, leaving the little mermaid as the third wheel on the outside.
The little mermaid's grandmother takes over the role of the sisters in the original fairytale, and visits the sea hag to bargain for the little mermaid's life. In another interesting twist, the Grandmother sacrifices fifty years of her lifespan to the sea hag in return for the knife, which (unlike the original fairytale) will not kill the prince, just transform him into a merman and make him instantaneously fall in love with the little mermaid. That's actually a pretty sweet deal, and changes the dimensions of the choice she has to make.
Then the little mermaid sees how much the prince and princess are in love, realising that what they have is the real thing. The little mermaid can't bring herself to destroy their true love, so she throws the knife away. I personally like this little turn, because here the little mermaid is a step away from getting exactly the happy ending she wants, but it'd be hollow and remove the prince's free will. The wedding proceeds as planned.
The little mermaid goes to the shore to await her death. But aha, this version has one last twist to throw at the audience, and this one made me sit up and shriek WHAT at the screen. To wrap it up, this adaptation makes it clear that Disney's animated version was not the first to shy away from Andersen's melancholy ending, though in this show they've got a hopeful open book ending where Neptune himself blesses the little mermaid and gives her back her tail so she can live out the rest of her life under the sea. And presumably, by the end of it, turn to sea foam on the waves, thus making me realise that this version doesn't mention anything about mermaids not having immortal souls, which I totally didn't notice earlier.