Just a little connection between the third film and the second.
The Little Mermaid III's Introduction
Melody loved-loved-loved to swim. Not in the cramped pools but in the big wide ocean, where the beaches made way for the wondrous waves. Ariel, her mother, as she now knew, was closer to the sea than she ever thought. Melody found out for the first time in her life that Ariel was once a mermaid, and not just any mermaid, but the youngest daughter of King Triton himself. That made Triton Melody's grandfather, she knew.
After the big adventure Melody had had, later discovering her mom's secret, all was well. There was no longer a wall between merpeople and the humans that lived in the castle on land. The princess was free to swim all she desired. And Ariel was comfortable to reveal everything to her daughter now.
That included everything from the adventures she had had in the sea in childhood and as a teenager. All about how mysterious humans seemed, and all about the troubles faced. From her mother, Melody had learned a lot about life under the sea.
Except there was one thing that kept nagging at her.
"Mom," Melody asked one night. "What happened to Grandmother?"
"She's gone," Ariel replied sadly. "Gone way before you were born."
"Why? What happened?" Melody inquired, frantic to know.
"It's a long story, sweetie. I'll tell you some other time. Now get some rest…"
"Oh, come on. Please? Mom, I want to know. What happened to her? Why did she die?"
"She was killed…by pirates." Ariel sighed.
"By- by pirates? But how? I thought you said you weren't allowed above the surface."
"Well, when I was little, even younger than you are now, things were completely different."
"Can you tell me? Every detail?"
"Oh, Melody, I don't want to disturb you with nightmares."
"I'm not scared. I faced a sea witch and lived," Melody grinned.
"But it's far too late," Ariel protested.
"I can stay up late, can't I? I think I should be allowed to if we call it a history lesson."
"Very well, you win, Melody," Ariel laughed.
Melody sat up straight, wide-eyed and fully interested in the story Ariel was about to tell.
"A long time ago, mermaids had contact with land all the time. Everything was perfect and peaceful…" Ariel sighed deeply as she remembered the beautiful times. "We enjoyed all sorts of things, but the one thing we treasured the most- on land and in the sea- was music."
"Yes, music. My mother used to sing to my sisters and me every night and every morning. And for fun, we would always sneak up on our parents to see them thinking they were alone. We'd spy on them when they kiss and love each other. My father gave my mother a beautiful music box that symbolized their profound love. Music was played all the time with the most angelic instruments you could ever think of. Everything flowed so wonderfully. Oh, I wish you could have seen it, Melody, you would have loved it.
"Then, one day, everything changed. Human pirates barged into the area in their monstrous ships, threatening us as they approached. We had to leave immediately before they attacked. Daddy- um, your grandfather-"
"Yeah, I know."
"-helped most of us escape. Everyone swam down, away to safety. But Mother was behind, watching in horror as the pirates began stealing our instruments- including the music box. The pirates missed the first time, so Mother took advantage of that to retrieve it. But as she got it-"
"Oh, no," said Melody. "You mean…?"
"Yes. It was terrible and the saddest day of my life. She never got the chance to escape when the ship struck her."
"What happened to the music box?"
"It was saved. My father took it as all that was left of her. Then, he set up new laws to prevent such dangers from happening again. So music was banned, as well as going up to the surface."
"How could you live with that for so many years?" Melody cried. Years without music? How awful! How could her mother have put up with that? Singing was her mother's favorite pastime!
"It was long and hard, but I did. Not all the time, though. The music rule was gotten rid of after…um, Melody, now you know what you asked for right? So now would be the time to go to sleep…"
"Aw, but you got me too hooked to stop now!" Melody objected.
Ariel chuckled. "I guess I should have saved that for later, huh? I knew telling you the story would be a bad idea."
"Okay, fine. But this is the last freebee, deal?"
Melody nodded eagerly. Then Ariel told her of what happened next (which is the whole movie of The Little Mermaid III).