A brilliant scientist named Dr. Komyoji has invented a robot with a \"conscience circuit,\" a special chip that allows him to think and feel like a normal human. This robot, named Jiro, is destined to endlessly fight Professor Gill, the leader of Dark, an underground crime organization armed with deadly androids. Dr. Komyoji?s daughter, Mitsuko, is left with the task of caring for Jiro?and finds herself slowly falling in love.