It's the near future and robots have become a part of everyday life in Japan. We're introduced to Tenma Umatarou and Ochanomizu Hiroshi, two teenage geniuses who work in Lab 7 at the renowned Nerima University, a school dedicated to studying and developing advances in robotics technology. Tenma and Hiroshi are planning to reveal their newest robot, model number A106 (or "six" for short) to the world, which utilizes their latest A.I. interface, code-named the "Bewusstsein" system, as well as having superheroic-style programming.
However, they put so much money into this project that they still have to work part-time jobs in order to pay for everything. Their jobs this time being to put on costumes and participate in a parade. As such, Tenma decides to put A106 in his costume and lets it do his job for him, but when danger breaks out at the parade, A106 can't stand idly by, and swoops in and saves the day, much to everyone's surprise.