5x08 "Secret of the Ruby Reef"
Tritannus makes a foray into the underwater palace of the King Neptune and his family transformed into mutants. Then, with the magic of his trident absorbs the powers of the sword of his father Neptune. The Winx go to Melody, engaged in the search of the second gem, the gem of the Empathy. During a confrontation with Tritannus, Musa was hit by a powerful spell and turns into a terrible monster, dedicated to destroy the Winx. Daphne is captured by Tritannus and the evil Trix.
5x09
At the Alfea College, Stella organizes a fashion show, but not as successful as hoped. While looking for ideas for new designs, she's transformed into a three years old girl by an Age Change object. In the depths of Zenith, the Winx, supported by specialist Roy, faces the mutants in a fight to the death. Bloom has the impression that his sister Daphne is in a situation of extreme danger and she's trying to contact her telepathically.
5x10
The Trix want to steal the magic of Bloom's Christmas, because they believe it is a powerful spell to increase their powers. At Alfea, the Winx are besieged by terrifying dragons of ice. Will Bloom celebrate Christmas with her family?
5x11
Daphne is questioned by Tritannus and the Trix who want to steal the secret of the Sirenix power. The Specialists' aerobatic is ruined by the intervention of Trix with a spell that transformed the Windrider into terrifying black lions. The Winx, on a mission on the sea depth of Lynphea, hoping to find the gem of Courage, find a voracious marine plant.
5x12 "The Domino Ceremony"
In the palace of Domino takes place a royal ceremony, and the girls wearing their princely clothes, but in the meantime the riddle connected to the third Sirenix gem is revealed and Bloom was forced to leave the party and go to a submarine place called the Great Yellow Barrier. At the depth of the ocean of Domino, the Winx must conquer their fears and overcome an extreme courage test.
5x13 "Crossing the Sirenix Gate"
The Winx turn on the source of the lake Roccaluce to open the Sirenix portal to the Infinite Ocean, but, Tritannus precedes them and with his trident absorbs the power of the source of the lake, which is beginning to dry up. The Winx, aided by their respective guardian, will try to do everything possible to restore the source Sirenix, save the lake and enter to the Roccaluce Infinite Ocean. Meanwhile, Tritannus sucks the power of Daphne and gives it to the Trix becoming stronger than ever and follows Tritannus to the Infinite Ocean.
