Prometheus is forced to land on an alien world, where the local Stargate is the team's only chance of returning home -- though the local population believe the gate to be a myth.

Carter is injured when the Prometheus is attacked by an unknown ship, and awakens to find herself stranded alone in deep space.

Anubis begins a systematic assault on Earth, and the planet's only hope of salvation depends on whether SG-1 can find the Ancients' mythical Lost City.