When Megan winds up her antique music box for the first time, she hears a tiny voice calling over the sound of the music - it is the Fairy Queen of the Land of Eight Kingdoms, a magical place far away! She has been imprisoned in the box by the evil enchanter Sorcero, and needs Megan's help. This time, Megan becomes a mermaid and is sent to the Emerald Seas. Here she must help a mermaid called Celeste, who is always telling tall tales. When Celeste tells her friends about seeing a terrifying sea monster, no one will believe her - but this time she's telling the truth! It's up to Megan to befriend the creature to help break Sorcero's spell.