A Bad Spell for a Worst Witch

A bad spell for a worst witch Mildred Hubble returns to Miss Cackle's Academy for Witches for her second year, determined to lose her embarrassing reputation as "the worst witch in the school". After Maud Moonshine and Enid Nightshade arrive, the three bump into two first-years (one of whom reminds Mildred very strongly of someone, the other with ginger frizzy hair in bunches). The one who seems familiar bursts into tears and clings onto Mildred when she hears that a lot of the teachers (including Miss Hardbroom) are quite strict. Mildred also accidentally slips a made-up story about Miss Hardbroom turning a student into a frog when she was just two seconds late for a lesson. To the girl's horror, they also learn that Miss Hardbroom will be replacing Miss Gimlett as their form-mistress for their second year.
The next morning, a fire bell rings. Mildred scrambles into her clothes but notices outisde her window Miss Hardbroom standing in the playground surrounded by hazy purple smoke. Thinking she is in a state of shock, Mildred tries to douse her in freezing cold water but the bucket slips off her broomstick and lands with a clang on Miss Hardbroom's head. After witnessing the bucket incident between Mildred and Miss Hardbroom, Ethel Hallow confronts Mildred at lunchtime saying that the girl she told the frog story to was her younger sister, Sybil Hallow. After prodding at Mildred, Mildred loses her temper and insults Ethel's family ("All you Hallows are weeds, weeds, weeds!").
After an unfortunate flying lesson, where Tabby makes another terrifying attempt to avoid sitting on the end of the broomstick, Miss Hardbroom sends Mildred to her room to calm down. When sitting in her bed, however, Mildred accidentally falls asleep and doesn't hear Ethel creeping into her room. Mildred is awoken by her bedroom door shutting only to find that everything looks giant-sized, even Tabby. She peeks in the mirror only to find that somebody has turned her into a frog. Whe