The direction of this Cartoon is in the hands of Tatsuo Ono, on a subject by Tetsu Kariya and Shigeru Tsuchiyama. The scripts are written by Ohikara Matsumoto, Noboru Shiroyama, Soji Yoshikawa and Siji Matsuoka and the drawing is by Takashi Kakuta, Konio Okoto, Isao Kanero, Toshio Kobayashi and Tesuo Shibuna.
The sovereign of planet Apolon discovers a source of immense power which he calls "Heart of Energy". As a consequence, a terrible war breaks out and all he can do before dying is to hide his extraordinary discovery in the breast of his young son, whom he then manages to send to Earth.
Years pass by and the Prince, unaware of his origin and bearing the name of Takeshi, spends his time playing football with his friends. One day, while Takeshi is alone pondering on the football pitch, the sky opens and flying towards him comes a kind of knight on a winged War-horse. The sword of the fairy-tale fantasy lodges in the breast of our young hero, who loses consciousness. On awakening, he discovers that in the place where he was touched by the sword there is now a strange sun-like symbol. After this incident, Takeshi meets Labhi, a scientist from Apolon who managed to flee from the war and who reveals to him his origins. He is now in a position to sit at the controls of the powerful robot Diapolon in order to defend the world and himself from all those who want at all costs to seize the power hidden in his breast. The robot is made up of three different parts, Edda (head), Trangu (trunk) and Legga (legs) piloted by Takeshi and two friends of his. The war will at last be won and the Queen, Takeshi’s mother, finally freed after a long imprisonment.
