Medabots are powerful robots endowed with artificial intelligence via special "medals," and they serve at their owner's whim. They are most frequently employed in "Robbatling," a popular combat sport in which two medabots battle each other. In the professional circuit, Medafighters utilize their Medabots to qualify for the World Tournament, competing among the elite to secure the championship title. Elementary school student Ikki Tenryou has just acquired his first Medabot: Metabee, an obsolete model lacking a medal. Fortunately, Ikki manages to locate a medal in a nearby river; however, upon inserting it into Metabee's head, the robot begins to display strange behavior. Short-tempered and rebellious, Metabee refuses to follow Ikki's commands. Nevertheless, to ascend the ranks toward the World Tournament, Ikki and Metabee must learn to cooperate, regardless of how daunting the task may appear…