It's potions class and Drusilla turns into a tree. Ethel points out that the dangers of turning into a tree include getting chopped down, woodpeckers, etc... Miss Hardbroom asks how they would be able to tell which tree Drusilla was if they were in a forest. Mildred says she'd be the one that dropped a branch on them. HB doesn't think that's funny, and makes Mildred drink her tree-turning-into potion next. Mildred turns into something ""prickly and annoying"". HB tells the class that they're getting a student teacher from Weird Sister's College named Gabrielle Gribble. Not too long later, the staff discuss the new student teacher, and Miss Cackle says that Gabrielle's last assignment didn't go too well, and that, as a favor to the college, they're letting her have another go at Cackles. Miss Crotchet gracefully moves so that Miss Gribble can have the broken chair. Gribble arrives, and everyone but Miss Hardbroom leaves (because the bell rings). Gribble's late because of the up draft outs