I've just read this for the first time. I thought it was a very good story, much one of EBD's better stand-alone books, but the ending was completely bonkers!
Judy gets off to a bad start at her new school. when she breaks a vase belonging to one of the in-crowd. When there's then a spate of theft and vandalism, she's the prime suspect. It's obviously going to turn out that she's innocent, so what's going on? It turns out that a lady living nearby has got a pet monkey, which has got out of her house, climbed up a ventilation shaft into the school (on numerous different occasions), got into classrooms and dormitories without being noticed and smashed vases, stolen exam papers, spilt ink and run off with a copy of the Bible! OK, it's not quite as bad as Professor Richardson going off in a spaceship, but it's hardly very likely

.
Just wondered what anyone else who'd read this made of it. It was very good apart from the silly ending!