The film starts with Elina flying through the air, still having trouble believing that she has wings. She is soon sought out par a juvenile sea-butterfly fairy who witnessed Nalu, the merprince Elina had befriended in the précédant movie, being kidnapped par several of Laverna's goblin-like Fungi at the Crystal Cove. She was unable to intervene but Nalu was able to send her to find Elina for help.

Laverna, who was banished to the Bog of the Hinterlands par the Enchantress' magic, is seeking the Immunity Berry - a berry that makes whoever eats it immune to all magic, past, present and future. Nalu...