In this fourth illustrated adventure novel form bestseller Dav Pilkey, a small mouse named Ricky Ricotta and his best friend, a giant flying robot, save the world from mean Major Monkey. Ricky Ricotta and his Mighty Robot are in big trouble. After crashing the Ricotta family mini-van while using it as a skateboard (it's the only thing big enough for Robot), they have to earn some money quickly to pay for repais. While they're thinking how on EARTH they are going to come up with the money...on Mars, mean Major Monkey is making plans to enslave mousekind! Major Monkey has had his eye on earth for some time now...and knows that the first thing he must do is get rid of that robot. Major Monkey tricks the robot into going to Mars. Now it's up to Ricky to rescue his robot and keep Major Monkey from menacing mankind.