The Winx Club is struggling with a terrible mystery… The archenemies of the Winx Club, the Trix, team up with the evil nymph Politea and find out that it doesn't take all that much to defeat the fairies once and for all and become invincible: just a pearl hidden in the depths of the Infinite Ocean! As small as it is powerful, the Pearl of the Depths gives enormous powers to those who possess it!