Prez knows that the best way to keep track of things is to make a list. That's important when you have a grandfather who is constantly forgetting. And it's even more important when your grandfather can't care for you anymore and you have to go live with a foster family out in the country.Prez is still learning to fit in at his new home when he answers the door to meet Sputnik—a kid who is more than a little strange. First, he can hear what Prez is thinking. Second, he looks like a dog to everyone except Prez. Third, he can manipulate the laws of space and time. Sputnik, it turns out is an alien, and he's got a mission that requires Prez's help: the Earth has been marked for destruction, and the only way they can stop it is to come up with ten reasons why the planet should be saved. Thus begins one of the most fun and eventful summers of Prez's life, as he and Sputnik set out on a journey to compile the most important list Prez has ever made—and discover just what makes our world so remarkable.