Kagaku ninja tai Gatchaman

Because his father is hurt, Ryu gets into the Horned Tank and goes back to his native fishing-village. However, in the sea around the village, Galactor plans to destroy a gas chamber and let the land sink into the sea. When Gel Sadra sees the G-5 heading towards the village, she thinks that the Science Ninja Team got wind of her plan. Ryu has indeed noticed some strange bubbles and Nambu tells him that he will send the God Phoenix to investigate. Gel Sadra charges two assassins with infiltrating the village and aiming at Ryu. Opposing the attacking Galactor, Ryu pretends to be weak and gets out of the difficult situation because the assassins start to doubt whether he really is a member of the Science Ninja Team. However, shortly thereafter, his father and younger brother are abducted by Galactor. Ryu follows them and finds out that a petroleum tanker at sea is actually the Galactor base. In order to save his family, Ryu sneaks into the base.