In Season 5, after learning that their Believix powers are less stronger and effective underwater, the Winx Club will go on a quest to find the ancient Sirenix transformation and magical power. To help the Winx, the Sirenix Book gave each of the Winx a Sirenix Box which contains their Sirenix guardian, and the Guardians of Sirenix granted the Winx the power of Harmonix that will allow them to fight in mid-air, on the land and under the water. Once the Winx did all the required tasks for Sirenix, they opened the gate to the Infinite Ocean thus enabling them to earn Sirenix. They eventually succeed in their goal and obtain Sirenix.