The Asgard aid Earth in negotiating a nonagression treaty with the Goa'uld System Lords.

The Tok'ra war with the Goa'uld escalates, and the rebel faction sends Daniel Jackson to a secret meeting between the System Lords.

Dr. Jackson's undercover mission to a Goa'uld summit is complicated by the arrival of a surprise guest. The rest of the team face a full-scale invasion of the Tok'ra homeworld.

A charismatic Jaffa leader seeks to forge an alliance between Earth and his rebel followers, winning the allegiance of Teal'c and Bra'tac.

SG-1 is called to defend the people of Abydos from the Goa'uld once again when they learn that Anubis, in search of a powerful device, is about to attack.

While searching for the Lost City of the Ancients on a distant planet, SG-1 is stunned to find Daniel Jackson alive and in human form but stripped of his memory. O'Neill convinces Daniel to return with them to the SGC, where he is reinstated for a daring mission to destroy Anubis' powerful new super-weapon!

Carter and Teal'c go in search of the Asgard to try and save Colonel O'Neill, but discover that the Asgard's enemy has returned with a vengeance. The System Lords seek an alliance with Earth against a common enemy.

While the Goa'uld threaten to attack Earth, SG-1 and the Asgard make a last, desperate stand against the Replicators, which have captured Major Carter and invaded the last outpost of the Asgard civilization.

The Replicators begin a systematic attack of the Goa'uld, forcing Baal to come to Earth for help. The Jaffa Resistance risk their entire movement in an attempt to retake a holy city in Baal's domain.