Sgt. Keroro, commanding officer of Planet Keron's invasion force, has a problem. After blowing his cover and losing his top-secret weapon, the frog-like alien has been cut off from the homeworld. To make matters worse, he's lost communications with the rest of his platoon. Now he has taken cover in the Hinata family household, where in exchange for doing his share of the chores, he gets his own room from which to secretly devise new plans of world domination!