Join the Monster High ghouls on an all new aquatic adventure as they dive deep into the crystal deep blue waters of the Great Scarrier Reef. When the ghouls get pulled in the school pool, they find themselves transported to a world of corals and florals - a wild underwater wonderland! But Lagoona is not there to see the sights - she's on a mission of the heart, as she realizes she has come home! She must confront her childhood nemesis and bully, come to terms with her own freaky flaws, win an aquatic dance extravaganza, and fight a terrible beast from the deep. So take the plunge - you won't believe what awaits you under the waves!

New characters introduced in this movie are Posea Reef, the daughter of Poseidon, Kala Mer'ri, the daughter of the Kraken (but it is written in her profile as "Confidential".), and Peri and Pearl Serpentine, the two-headed daughter of the Hydra.

imdb:tt5475710