Earth is once again threatened by an extra-Solar threat as a new mothership arrives. The Earth Space Defense, established after the first invasion, must fight against the alien attackers. With the help of veteran fighters and new recruits, they attempt to stop the aliens before they destroy the planet. The pilots face heavy resistance and find themselves in a trap as they try to kill the Alien Queen. In a last-ditch effort, they manage to lure the Queen to an isolated area and detonate a nuclear bomb, sacrificing their lives to save Earth. Despite celebrations, the Queen survives and goes on a rampage, but is ultimately defeated. The threat is eliminated, and Earth is saved once again. With the knowledge from a captured alien sphere, the pilots and scientists decide to take the fight against the aliens into space.

Aliens invade Earth and deploy destructive ships in major cities. Mankind fights back with the help of a satellite technician, a fighter pilot, and a scientist. They discover that the aliens are using Earth's technology against them. The survivors launch a counterattack but fail to penetrate the aliens' force field. However, they manage to capture an alien and take it to Area 51. The president learns about the aliens' plan to destroy Earth and orders a nuclear attack. The survivors come up with a plan to disable the aliens' shields and destroy the mothership. They successfully execute the plan and defeat the aliens, saving the world.