When Molly Holmes moves with her family to Horseshoe Bay, her grandmother gives her an enchanted shell necklace that magically transforms her life. The power of the necklace transports Molly to the Undersea Kingdom, where she discovers that she is a Secret Mermaid and meets lots of new mermaid friends. But the evil Dark Queen Carlotta seeks to steal control from the good Merqueen Luna, by seizing the magic pieces of conch shell that help protect the...

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. Readers will be enchanted by Molly...

Molly is called back to the ocean by the Mermaid Queen because the mermaids desperately need her help. All the whales, penguins, turtles, seahorses, dolphins and octopi have completely vanished from the seas and no one knows why - but they suspect dark magic is at work.