Triton is about to leave to watch the turtle races, while everyone else in Atlantica is partying with music, dancing and games.After Triton leaves, Ariel and Flounder go exploring. As they find crystals near an undersea volcano, a mysterious voice calls out to them. When they investigate, they see two glowing eyes of some creature trapped in the volcano. Flounder warns Ariel that there are legends of a horrible monster that was imprisoned in the mountains by ancient merpeople.
- Ariel: Oh Flounder, that’s just a silly story grownups tell to scare little fishes.Flounder: Well, it works.
The Manta swims off towards Atlantica, and stops to talk to an exercising octopus. The Manta compliments the octopus’ tentacles, and persuades it that it is much better than a swordfish. After the octopus swims off, the Manta then speaks to the swordfish, telling it that it is much too special to hang around with a freak like an octopus. The Manta continues spreading discord around Atlantica by manipulating the sea creatures to have inflated opinions of themselves and disdain for those around them.
Ariel and Flounder try to stop the Manta by catching him in a seaweed net, but the Manta breaks free, boasting that he is more powerful than friendship.
- Evil Manta: Oh, I just love spreading the shadow of prejudice. It blots out friendships before they’ve even begun.
- Evil Manta: I love my work. Now, only the little mermaid remains.
Ariel and Flounder think back to how they first became friends. As a young fish, Flounder used to be afraid of everything, which once got him separated from his school when he was startled by a mermaid swimming by. That mermaid was Ariel, and she soon convinced Flounder that the sea was made up of more than just big and little fish. Ariel showed Flounder the way back to his school, and the two became friends.
Returning to the center of town, Ariel leads Atlantica in a song about harmony and diversity. Before long, the various sea creatures join in the song and celebrate their differences instead of quarreling.
The Evil Manta gloats that once he charms Ariel his victory will be complete, but suddenly he hears music, a sound that he hates.
- Evil Manta: I hate singing. Hate it! I hate love, and friendship, and do I ever hate…that little mermaid!
King Triton comes home to see that once again Atlantica is the happiest place under the sea.
Tropes
- Fantastic Racism: The Evil Manta causes the sea creatures to become prejudiced against each other.
- Nice Job Breaking It, Hero: Ariel releases the Evil Manta, thinking that the story of it being a monster was just a myth.
- No-Sell: Flounder is able to resist the Evil Manta’s powers of prejudice.
- Off-Model: Ariel’s eyes are grey in a few scenes, instead of their usual blue color.
- Power of Friendship: The bond between Ariel and Flounder is too strong for the Manta to break.
- Power Of Music: Ariel manages to break the Manta's influence by leading Atlantica in a song about harmony.
- Sealed Evil in a Can: The Evil Manta was sealed away inside an underwater volcano long ago.