Winx Club: The Secret of the Lost Kingdom (2007) on Netflix

Plot summary

Bloom is searching for her birth parents, King Oritel and Queen Marion, and her friends join the search: Stella, Flora, Musa, Tecna and Aisha. They seek Hagen, the blacksmith who crafted Oritel's sword, and slip into his castle, where they are taken for intruders until Faragonda, an old friend of his, steps in. Hagen tells them he cannot help, and Bloom, blaming herself, runs off. The other Winx graduate as guardian fairies of their home planets, while Bloom stays at Alfea, where Sky urges her not to give up. She visits her adoptive parents, Mike and Vanessa, on Earth and dreams of her sister Daphne, who says their parents are alive and tells her about the Book of Fate. Her friends gather at her house for her nineteenth birthday and agree to support her plan.