Once upon a time, a highly developed advanced race, Ancient, was based on Earth. Millions of years ago, for some reason, they left Earth and went somewhere, leaving only an outpost at the South Pole. After Jack O'Neill wiped out an Ancient weapon from the military outpost to destroy the fleet of the Goa'uld who came to attack the area, the countries cooperated to establish the Antarctic Alliance to study Ancient technology in the outpost and promote international cooperation and peace. In the course of their research, they discovered where Ancient went after leaving Earth-the Pegasus galaxy. So, in order to explore the buried history and explore the unknown world, countries formed Atlantis exploration teams to reach the city of Atlantis, which flew away from the earth millions of years ago through the Stargate. Unfortunately, the arrival of earthlings awakened a group of monsters who ruled the Pegasus galaxy, Wraith, technologically advanced, physically strong, rough and cruel, unfaithful, and sucking human life with humans as livestock. Ten thousand years ago they defeated Ancient and forced him to flee back to Earth, and the expedition discovered an astonishing fact.