When evil robots make Bryce's legs hurt, his worried parents drive him to the hospital. There Doctor Happy sticks him with needles and tells him he has to stay for 10 days! Bryce's father explains to him that some of the needles are filled with fierce Ninjas, who will use their swords and nunchuks to kill the bad robots. Bryce can feel the battle raging inside him. But before very long the Ninjas are winning. Bryce feels good again. He can go to school, play hard, tease his baby brother and roughhouse like any other four-year-old goofball. Bryce knows there might be some robots still hiding in his blood, though. So for a while Doctor Happy will have to send in more tough Ninjas to help Bryce fight until every last robot is dead.