The Winx Club must decide to open the Sirenix book wholeheartedly. So they decide to go stand in for Alfea in the ancient ruins of Graynor, fairies from all over the magical dimension must win a competition the Winx Club try to find the creature of the Rainbow Mantle. The Trix attack Stella, Musa, and Tecna, and start to fight. In the mist, Bloom saves a horse, who reveals itself to be the creature when the Trix try to attack it, it heals the Winx Club, and they win and head back to Alfea. Upon opening the Sirenix Book, they learn the must earn the Sirenix transformation and power before the next lunar cycle ends, or they lose all of their magical powers forever. To begin their quest, they must first find three mystical gems known as the Gem of Self-confidence, the Gem of Empathy, and the Gem of Courage. They split up into two teams: Flora, Tecna and Musa try to find the Shimmering Shells while Bloom, Stella and Aisha go to Andros' oceans to try and find the Gem of Self-confidence, and achieve their newly acquired Harmonix abilities for the first time.