What it takes to become unstoppable and vanquish the fairies is a Pearl hidden in the depths of the infinite ocean: the Trix witches and the nasty nymph Politea team up. The Pearl of the Depth, which is both little and powerful, grants immense powers to its owners! When it comes to the Winx, time is of the essence. How can they foil the evil intentions of their foes before it is too late? The Winx are set to go on their most perilous adventure ever!