This is, I think, the first episode of the series that I'd ever seen, and I think one of the more unusual ones because of the creepy feeling thing going on in the second half.

Ariel's relationship with her father is in the spotlight. When the episode opens they're in a good place, with Ariel cheerfully asking Triton to go with her on a swim, though he apologizes that he can't join her because of other things he has to do. Ariel ends up exploring with Flounder, and finds a magnifying glass (or a "biggermajigger") that she brings back to the palace. When Triton sees her admiring it, he loses his temper and destroys it without a second thought.

Ariel gets understandably upset, and swims off with Flounder. Above a deep canyon, Flounder spies a shiny thing just inside the walls of the canyon. It turns out to be a gold charm bracelet, which is stuck to a piece of coral. Ariel takes the bracelet, except for one piece which breaks off, and is immediately enchanted by how pretty it is. But when the bracelet refuses to come off, she realises that she can't go home because Triton would blow his top again.

Eventually Ariel realises that she needs to piece she left behind at the canyon, which is the key that is supposed to open the bracelet. When she returns to collect it, she is sucked into a powerful whirlpool and ends up trapped in what is the underwater equivalent of Alice's Wonderland, and I mean the original creepy-bizarre Wonderland, not the Disney one.

Unknown to Ariel, Triton is busy angsting over the fact that he owes Ariel an apology, and can't seem to be able to give one without losing his temper. Still, he waits for her to return.

It's really sweet that the series shows true affection between Ariel and her father, instead of turning into a 2-dimensional thing where he's always scolding her. They are much more similar than they realise, which makes the events of the film all that more heartbreaking.