While SG-1 team is trying to destroy the Ba`ala, the last Lord of Gualds, Teal'c and Vala mysteriously disappear. Carter, Daniel and Mitchell realize that time continuum was broken and the Research Star Gates Programme was erased from history. The heroes are trying to bring their uneasy idea to the authorities, but cruisers Goa'uld headed by Ba'al, Queen Katesh and Prime Minister Teal'c come into orbit. The SG-1 team must find the Star Gates and restore the correct course of things before the world is enslaved by invaders.