As Molly's underwater quests begin, she must help fellow mermaid Ella recover her piece of the magical conch shell in order to protect the coastline and prevent floods. But the Dark Queen's army of menacing sea creatures is hot on the mermaids' tails. When Ella is attacked by a bewitched orca and flung onto the nearby beach, Molly must learn to harness the mysterious powers of her magic conch necklace to save her.