The Winx Club is struggling with a terrible "mystery" that will make your heart beat faster! The archenemies of the Winx Club, the Trix witches, team up with the evil nymph Politea and find out that it takes very little to defeat the fairies once and for all and become invincible: a Pearl hidden in the Depths of the Infinite Ocean! As small as powerful, the Pearl of the Deep gives enormous powers to those who possess it! The Dark Magic team is complete: Trix, Politea and Tritannus, not bad as group... 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 conquer the magic Pearl before her enemies and save prince Sky, who has been captured by the Trix and imprisoned in the Ocean. The Winx have no time to waste: how will they stop their enemies’ plans before it's too late? The answer is not simple: with a twist, Politea is preparing to seize power all for herself, betraying allies and polluting the oceans to regain strength and power. Get ready: the Winx most dangerous mission of is about to begin!