When Wanda brings her new ladybugs to school, she just wants Ms. Frizzle to give her some hints on caring for her insect pets. Instead, the whole class gets field trip. They find out pretty quickly that lots of insects eat other insects for lunch. And, there is a little issue of spiders, too. Yikes! It might be disgusting, but Wanda has to admit that the world of insect invaders is amazing.