After a horrifying PredAlien crash-lands near a small Colorado town, killing everyone it encounters and producing countless Alien offspring, a lone Predator arrives to "clean up" the infestation.
Ba'al travels back in time and prevents the Stargate program from being started. SG-1 must somehow restore history.
SG-1 searches for an ancient weapon which could help them defeat the Ori, and discover it may be in the Ori's own home galaxy. As the Ori prepare to send ships through to the Milky Way to attack Earth, SG-1 travels to the Ori galaxy aboard the Odyssey. The International Oversight committee have their own plans and SG-1 finds themselves in a distant galaxy fighting two powerful enemies.
