It is the year 2194. The Gamilons, an enemy of undetermined form, begin an invasion of Earth. The nations of Earth pool their forces and fight back, but their armies are defeated and most of humanity wiped out.
Five years later, in 2199, the Earth has been polluted by space-to-planet bombs, and those who remain alive have fled underground. Even the former top pilot, Susume Kodai, has left the military. One day as he is exploring above-ground, a mysterious object falls out of the sky. This is a communications capsule from the planet of Iscandar, 148,000 light years distant.
Apparently on Iscandar is equipment that will eliminate the radiation. The Defense Force of Earth equips the Space Battleship Yamato with a previously unknown propulsion system, a wave-motion engine based on plans found in the capsule. Kodai rejoins the Force, and resolves to set out aboard the “Yamato.” With the fate of the Earth in their hands, the crew blasts off for distant Iscandar. They have one year until radiation drives humanity to extinction. Kodai great battle has begun. Carrying humanity last hope with it, the Yamato blasts off!