Horror that is out of this world!

In Scottsdale, Arizona, Shelby Crusado has a sneaking suspicion: she thinks her teacher is a robot, but no one will believe her.
        Well, Shelby is wrong. Her teacher is something much worse than a robot, and when Shelby and her friend Joey discover what is really going on, they realize that the entire world is in danger of an alien invasion. Now, they're caught in an all-out battle to stop the sinister aliens from a planet 3 million miles away. Intergalactic space travel, strange creatures from other worlds . . . Shelby and Joey have their hands full.
        But can two kids from Scottsdale stop an army of bizarre creatures from taking over the planet?