Robert hates school, so he sends a robot?Robokid?to school in his place and unwittingly helps to defend Earth from invasion by the Xargians. But the school bully, Barry, is in league with the Xargians who send him a robot battledroid to exterminate Robokid?and the entire population of Earth. Can Robokid defeat Battledroid? Can Robert save Earth from the Xargians?