Sci-fi adventure set featuring the SG-1 crew. The film begins with SG-1 attending the execution of Ba'al (Cliff Simon), the final Goa'uld System Lord. When Teal'c (Christopher Judge) and Vala (Claudia Black) suddenly disappear into thin air, Carter (Amanda Tapping), Daniel (Michael Shanks) and Mitchell (Ben Browder) travel back to Earth to discover that history has been altered, and, in this new timeline, the Stargate programme has never been discovered. When they try to convince the military that the timeline has been altered and that Ba'al is responsible, hundreds of Goa'uld ships suddenly arrive in orbit, led by Ba'al, his queen, Qetesh (Vala), and his first prime, Teal'c. It's now up to O'Neill (Richard Dean Anderson) and the rest of the crew to find the Stargate and set things right before the Goa'uld take over the world.