A disturbing celestial phenomenon has caught the Winx Club’s attention: stars are vanishing from the night sky. As they investigate, a chilling connection emerges – the reappearance of the formidable Valtor seems to be at the root of this cosmic crisis. Their search for answers leads them to Lumenia, the dazzling heart of the Magic Dimension and the source of light for Stella's beloved Solaria. There, Lumenia’s queen bestows upon the fairies a powerful new ability: Cosmix, granting them the strength needed to safeguard billions of stars across the universe. During their journey, they encounter Twinkly, a charming golden being intrinsically linked to Lumenia’s vital energy and offering invaluable assistance along the way.