Asamoto Soshi and Izawa Riko were called back to Japan after they had completed their studies in Paris. They fall in love in between and planning to marry soon. In addition, Kamiya Ayumi, a brilliant scientist and her assistant Nanase, they develop many new models of robot but Ayumi is most interested in "Tenjo Night" which have the human feeling. One day, Riko is assaulted by delinquents. A passer-by comes to the aid of Riko, and the savior is none other than robot "Tenjo Night".