Since the discovery of Getter rays and their widespread use as an important energy source, mankind has gone through more than half a century. However, the mysterious alien creature Inventor (visitor) began to invade the earth from the moon, and mankind was on the verge of crisis. So, people spontaneously created a large number of SuperRobots to fight, and finally repelled these monsters. With the death of Dr. Saotome, the world's authoritative research institution for Getter rays, the Saotome Institute, was gradually abandoned. The culprit who killed the doctor that year was the former captain of the Getter team, Ryu Ryuma, who has now been sentenced to life imprisonment and is in prison. The Getter team, which once had the most powerful force in the war, was disbanded. One day, when former Getter team members Tomoe Musashi and Benkei Kurumi were transporting important military supplies, they met the long-lost Inventor again on the mountain road and were intercepted. Tomoe Musashi drove the Getter Unit 3 to fight. After a long battle, he was attacked by a huge robot in the middle of the battle. It was dark red and had devil wings on its back. It was the God Killer, the real Getter. Musashi, who was unaware of the situation, was severely injured, and the real Getter also took care of Inventor at the same time. His power was so strong that it was shocking. The operator turned out to be Dr. Saotome, who was supposed to have died three years ago. What happened? The mystery of Inventor's invasion of the earth and the secret of Getter's ray are about to be revealed. !