Sebastian is sad because he's a little crab, so Ariel goes to a cave where she becomes a sea witch. She puts a spell on Sebastian that makes him big, but the bigger Sebastian gets the less room their is for everyone in the sea.
King Triton wants Ariel to learn how to play the calliope, but Ariel wants to learn how to play the harp. She tries to learn the calliope and her bad playing wakes up an old ancient evil sea monster.
