Major Carter joins an alien pilot for a space race, where the winner is awarded a lucrative contract with the planet's most powerful corporation. But the rest of the team discovers that there is more at stake than the finish line.
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.
While Daniel finds himself in a mysterious diner suspended between death and ascension, Jacob's fate takes an unexpected turn, Jack and Sam consider their romantic lives, and Anubis unleashes his plan for galactic destruction.
An Air Force pilot attempts to reassemble SG-1 after they have gone their separate ways. An old "friend" arrives on Earth asking for Daniel's help in finding an ancient treasure -- and she won't take no for an answer.
An Ancient communications device renders Daniel and Vala unconscious, sending their minds to another galaxy -- where they inhabit the bodies of two people persecuted by the followers of an evil religion.
As the Ori plague spreads rapidly, SG-1 hopes that the Prior who caused the disease may hold the key to its cure. Gerak tries to rally the Jaffa to the Ori's cause, prompting Teal'c and Bra'tac to initiate a resistance.