Winx Club Season 5 Episode 4 Return to Alfea Episode Title:Return to Alfea.Episode Description:The Winx Club return to Alfea and discuss with Ms. Faragonda about their new threat, Tritannus. Faragonda tells them they will need to acquire an ancient power called Sirenix to defeat Tritannus. She also informs the Winx the last fairy to acquire the power was Bloom's sister, Daphne, she knows where to find the Book of Sirenix. Bloom meets with her sister, who warns her to not seek the power, but Daphne eventually tells Bloom the Book of Sirenix is located in the Magic Archives of Alfea. The Winx, along with Sky, Brandon, Helia, and Princess Krystal, who is the princess of Flora's realm, Linphea, go into the Magic Archive to begin their search. The Trix attack the Winx and during the battle Sky takes a blow to the head that causes him to lose his memory.