After their summer vacation, the Winx Club returns to Alfea to begin their second year.

They meet a new fairy, Aisha, who asks for their help in rescuing her Pixie friends held hostage by Lord Darkar. Lord Darkar is actually the "Shadow Phoenix" who wants to take control of the magical realm. In order to do so, he has to find out where the Pixies' Village is in order to steal the four pieces of Codex which open the portal to the Realm of Relix, where the Ultimate Power can be found.

The Trix also meets Lord Darkar and serves him. Meanwhile, Winx Club learn how to obtain their Charmix. A "new teacher" arrives in Alfea and turns Bloom into Dark Bloom to serve Lord Darkar. With Dark Bloom's help, Lord Darkar opens the portal to the Realm of Relix.