Gatchaman II (科学忍者隊ガッチャマンII, Kagaku Ninjatai Gatchaman Tsū, Science Ninja Team Gatchaman II) is the direct sequel to Science Ninja Team Gatchaman, set two years after the first television series. After the defeat of Leader X, he exacts his revenge by mutating a young girl into Gel Sadra, making her the new leader of Galactor. While Galactor returns, Dr. Nambu and the International Science Organization bring the Science Ninja Team Gatchaman back into active duty.