Every young girl dreams of a world where she's the boss, where she can make dragons appear with a snap of her fingers and disappear again before they eat her, where it's never time to do her math homework or dust the living room. For Noë Andrews, the virtual reality technology of the future makes that possible. Noë is used to playing in virtual simulations of all of her favorite books, and her teachers use VR as if it was nothing at all. It doesn't get Noë away from her bratty little brother or the bullies at school forever, but in VR all of her worries disappear for an hour or two.

Then, for her thirteenth birthday, Noë receives a blank virtual world that she gets to design from the ground up. She and her best friend Jonah have been waiting and planning for their own world for months. But when they meet Max, the new kid at school, they decide to let him join in.

The world they create together allows them to fight off predators and make friends with giant bug-people, wrinkly little blue aliens, and whatever else they decide to put into it. But when the bullies won't leave Noë alone, Max decides to take matters into his own hands. He secretly creates another alien species inside their world, one whose sole purpose is hurting bad people. Then he lures the bullies into the virtual world with him. They emerge scared witless and run to their parents and the school principal. Noë and Jonah are furious that they have gotten in trouble for something Max did without their knowledge, and they kick him and all of his creations out of their virtual world.

But things just aren't the same without Max. Jonah and Noë gradually learn that even a virtual world can't be limited to those things we think are happy, and that conflict is a part of life. They forgive Max, and he promises not to make any more violent aliens. He also swears that he won't lie to them about what he's doing, but they all know that their worlds will never be the same as they were before.