Mech Cadet Yu

"Every year, giant sentient robots from outer space come to Earth and bond forever with a brand new crop of cadets at Sky Corps Academy to help keep the planet safe. But this year, instead of making a connection with a cadet, one of the mechs bonds with Stanford, a young kid working with his Mom as a janitor at Sky Corps. Stanford has the opportunity of a lifetime but he'll first have to earn the trust of his classmates if he's to defend the planet from the monstrous Sharg."--Amazon.com.