he Winx Club embark on a mission to achieve Sirenix, a water based transformation that is strong and powerful enough to defeat the evil Tritannus and the Trix. The Trix's main leader, Icy falls deep in love with Tritannus. While the two other Trix members Darcy and Stormy are fustrated with their relationship. There are two new evolutionary fairy transformations in this season: Harmonix and Sirenix. The Book of Sirenix gave them Sirenix Boxes that holds guardians inside them to help them gain Sirenix, and much stronger Harmonix powers. Before they achieve Sirenix, they must find the Gem of Self-Confidence, Gem of Empathy, and the Gem of Courage. Unfortunately, there is a dark and evil curse upon Sirenix that left Bloom's older sister, Daphne, a disembodied spirit without a physical body.But there is a Sirenix book that helps them gain Sirenix, but there is a problem when they open the book *spoiler* Tecna opens it and it transforms her into a terrifying robot version of her self, making a mess in the Magic Archive the library in Alfea. When she had used its tremendous power to defend herself. Daphne was the last fairy to achieve Sirenix's ocean/sea-based transformation and enormous power until the Winx Club gain full access to Sirenix and cross the gate into the infinite ocean itself. Finally, the Winx gain Sirenix after activating the source of the power in Lake Roccalute where Daphne lives due to her connection to Sirenix. But Daphne gets locked up in the emperors throne, after Tritannus has taken away her Sirenix powers and given them to the Trix ( Icy, Darcy, Stormy ) Unfortunately, the Trix gain dark Sirenix with the help of Tritannus ( because he took away Daphne's Sirenix with his trident ) and plan to defeat the Winx Club. Tritannus is also son of king Neptune turned into evil form of his merman form. His tail also has purple pollution track but doesn't stay. He refuels by taking in pollution ( oil, gas ) with his trident from the help of Icy and the Trix. Also Roxy will not be a big character in this season she will only be appeared as a guest star. She will just be a student at Alfea. A new student she is not a main character anymore. But she will appear in later episodes or later seasons. Upset that he cannot activate the tremendous and limitless power of the Emperor's Throne, Tritannus must take the seals of the pillars of light, balance and control.Tritannus stole the seal of the pillar of light and Stella restored the pillar by using all of her sun energy giving light back to the pillar.Now Tritannus,is going to steal the second seal of the pillar of balance and next is the pillar of control to finally activate the emperor's throne.