After escaping from her scientist captors, Rat finds herself aboard a space station

When Rat—a lavender-colored, highly intelligent rat—escaped from her cage and found a hiding place in a nearby crate, she had no idea she’d be headed for the stars. A space station, she quickly discovers, is no place for a rat. It’s hard to find food amid the humans and robots aboard the craft, and even harder to move around undetected.
 
Meanwhile, Jeff, whose parents are scientists, is the only kid on board. He’s got no friends to play with, and his robot babysitter is constantly bossing him around. To make matters worse, all of his friends are off at summer camp back on Earth and too busy having a great time to email him. So Jeff is beyond excited when he gets an email from an anonymous pen pal. Little does he know that his new buddy doesn’t live on Earth—and isn’t even human!