Ethel receives a visit from Esmeralda, trying to convince Esmeralda to take the founding stone's magic which she refuses. The founding stone, a stone given to witching academies to fuel magic is found. Mildred returns to Cackle's, a much better witch than she was before. Mildred is brought back to Cackle's and finishes her first year. After Agatha annihilates the school due to no one liking her, Mildred and her classmates perform a spell which reverses all of Agatha's spell. Learning Agatha has become headmistress from her rival, Mildred returns to Cackle's, hoping to save it. Agatha comes to Cackle's, tricks Esmeralda, Ethel's older sister, into giving Agatha her magic and takes over as headmistress. Later, Mildred gets expelled for leaving the grounds without permission. She forms friendships with new girl Enid Nightshade but becomes Ethel Hallow's rival. Mildred struggles with tasks and work, not knowing about witching her whole life, unlike her classmates. With the help of her new friend Maud Spellbody, Mildred goes to an academy for witches and is admitted after she saves it from the headmistress Miss Cackle's evil sister Agatha whose magic is later taken away. Mildred Hubble learns about magic and witching, discovering she is a witch despite coming from a non-witching family. Netflix released the fourth series on 1 October 2020. The fourth series began airing on 27 January 2020. The third series began airing on 7 January 2019. The second series premiered on Netflix Australia on 27 July 2018. A second series began airing from 8 January 2018. The series premiered on CBBC on 11 January 2017. It was available to members in the UK, Ireland and Germany after its premiere on CBBC and ZDF. The series was made available to stream internationally on Netflix on 22 July 2017.

The series was an international co-production between CBBC, ZDF and Netflix. It is the fifth adaptation of The Worst Witch series after the 1986 television film, the 1998 television series, the 2001 television spin-off and the 2005 television spin-off. Based on novel series of the same name published in 1974 by Jill Murphy, the series follows Mildred Hubble ( Bella Ramsey (series 1–3), Lydia Page (series 4)) and her friends Maud Spellbody (Meibh Campbell (series 1), Megan Hughes (series 2–4) and Enid Nightshade ( Tamara Smart) and rivals Ethel Hallow (Jenny Richardson), Drusilla Paddock (Tallulah Milligan) and Felicity Foxglove's (Dagny Rollins) adventures and education at Cackle's Academy under caring headmistress Miss Cackle ( Clare Higgins) and strict deputy headmistress Miss Hardbroom ( Raquel Cassidy). The Worst Witch is a fantasy drama children's television series.

The worst witch at sea