The Winx, accompanied by Twinkly, reach Lumenia. There, Queen Dorana explains to them that the stars of the Magic Universe are in danger. She asks them to find out what has drained one of Lumenia's rivers of light, and the Winx find out it was because of a black magic sphere that blocks the flow of the river. After blowing up the sphere, they go underground where they battle two lava golems and a golem robot. After defeating the golems, Valtor's mark appears in the air, revealing to the Winx that he is still alive and back into action. After restoring the dried river of light, the Winx return to Dorana, who thanks them for saving the river. She then tells them that in order to save the stars, they will need a new power. Now that the river of light is restored and along with that Dorana's powers as well, she grants the Winx a new power: Cosmix.
