The Worst Witch (2017): Season 1, Episode 2

1 - 2: Selection Day: Part 2

Second part of the premiere episode... Miss Cackle's evil twin-sister, Agatha, plots to become the new headmaster of the academy, but Mildred saves the day and exposes her. In her battle against her sister, Agatha's magic turns against her and leaves her magic-less. After saving everyone, Mildred is accepted to Cackle's Academy and Miss Cackle and Miss Hardbroom tell Mildred's mother about existence of magic.