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.

Relations between the U.S. and Russia are strained when Russian military leaders claim that the U.S. government has been compromised by the Goa'uld.

Daniel is imprisoned on a world under the influence of the Ori, and the Prometheus is caught in a firefight when SG-1 tries to rescue him.