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 his home world. To make matters worse, he's lost communications with the rest of his platoon! But now he has taken cover in the Hinata family household. In exchange for doing his share of the chores, he gets his own private room...where he is secretly devising new plans for world domination!