It is 2020, and the battle between the Earthlings and the Zentraeds has ended for many years. The expeditionary force led by Rick Carter (voiced by Rick Hunter) is gathering, the Space Fortress 3 (SDF-3) has been completed, and a new era is coming. However, the expeditionary force's plan is quite difficult. Since almost all the weapons on Earth have to be taken away, there are many disputes within the army. In addition, Rick will also face personal problems. He is about to enter the marriage hall with his war partner Lisa (voiced by Melanie MacQueen), and his love with Mingmei will also come to an end. On the other hand, due to the rebellion and defeat of the Zentraeds, the robot rulers left Tyro and went to Earth. At this moment, the Invid fleet led by Regent invaded Tyro in order to find the flower of life. Regis was dissatisfied with Regent's reckless behavior and decided to leave him alone, and the war in the new era began... This film is the second part of the "Space Fortress" theatrical version.