The Winx Club is struggling with a terrible mystery that will make your heart beat faster! The arch enemies of the Winx Club, the Trix witches, team up with the evil nymph Politea and find out that, to defeat the fairies once and for all and become invincible, it takes very little: a Pearl hidden in the Deep of the Infinite Ocean! As small as powerful, the Pearl of the Depth gives enormous powers to those who possess it. The team of Dark Magic: Trix, Politea and Tritannus, are almost unbeatable. But none of them have come to terms with the true power of the Winx, the power of Love. Bloom is more determined than ever to get the magic Pearl before her enemies and save prince Sky, captured by the Trix and imprisoned in the Ocean. For the Winx, there is not a minute to waste: how will they stop the plans of their enemies before it's too late? The answer is not simple: with a twist, Politea is preparing to seize power all to herself, betraying allies and polluting the Oceans to regain strength and power. Get ready: the most dangerous mission of the Winx is about to begin.