Mrs. Jewls, who has a "terribly nice face" (2.1), arrives at Wayside School to take the place of former apple Mrs. Gorf.
The children on the thirtieth floor have been without a teacher for three days since they never told anyone what happened to Mrs. Gorf. You'd think they'd be thrilled to have a lovely new teacher, but since everything at this school seems to be totally backwards, the kids are terrified: "[…] They were terribly afraid of nice teachers" (2.2). Of course they are.
Mrs. Jewls, as it turns out, is equally terrified: "She had never taught cute children. She was horribly afraid of cute children" (2.3). Sounds about right for Wayside, right?
Both kids and teacher forget all this terror though, once Mrs. Jewls mistakes her entire class for a group of monkeys, assuming that they were "much too cute to be children" (2.5).
Mrs. Jewls refuses to believe that the children aren't monkeys, and it takes a lot of persuading to get her to change her mind. And once she changes her mind, she makes them take a test.
Jason comments that he "liked it better when she thought we were monkeys" (2.37). Jason, we're with you—if only all teachers gave out bananas instead of tests.