Students who have suspected that teachers hibernate over winter vacations, come In only two varieties, crabby or nice, and stay the same age forever will be assured by Evans that it's all true. Young Bradley sneaks away from his classmates during a field trip to Apple Island and discovers that it's a teacher training ground, with chalk mountains, a glue river, origami birds, underground reservoirs of paint, and a school where teachers are instructed in the finer points of marching in lines, assigning homework, and other skills. Worse, he learns that the nice teachers have all left and that the surly ones are plotting to take over the schools.