O’Neill and Teal’c risk their lives to keep the Replicator bugs from gaining a foothold on Earth, while Carter helps the Asgard fend off a Replicator invasion.

An alien artifact causes Daniel to disappear, and the team looks for help from his institutionalized grandfather.

SG-1 returns from a mission and discovers that metamorphic aliens have taken over the complex.

Apophis, SG-1’s greatest enemy, seeks sanctuary from Sokar and ends up near death in the S.G.C. infirmary.

O’Neill becomes the unwilling receptacle for a library of alien knowledge.

After gating to a world on the edge of a black hole, the S.G.C. cannot disengage the Stargate. All of Earth becomes endangered by the time-distorting gravity field.

SG-1 discovers an ancient artifact that takes O’Neill and the S.G.C. hostage.