One spits marbles. One rips up anything it can get its hands on. One shuts any door it sees, one shocks you with static electricity, and yet another echoes anything you say. What are they? Why are they here? Well, they're called Animalcules, Fi knows that, she doesn't know why or how she knows that, she just does. But why they're here is another matter entirely - she has no idea. Nor does she know how to get rid of them as they follow her wherever she goes. But if she doesn't figure things out quick, it's going to get real bad, particularly for the people in Mexico CIty who are now dealing with a building-size Animalcule destroying everything!