While SG-1 attends the execution of Baal, the last of the Goauld System Lords, Tealc and Vala inexplicably disappear into thin air. Carter, Daniel and Mitchell race back to a world where history has been changed: the Stargate program has been erased from the timeline. The remaining SG-1 members must find the Stargate and set things right before they world is enslaved by the Goauld.