When SG-1 is captured by the Goa'uld, a pair of scientists mount a rescue operation ... whether they're wanted or not.

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!

The team returns to Jonas' homeworld when they learn that the Goa'uld are after its naquadria. When Jonas is captured by Anubis, Daniel is his only hope.

O'Neill goes to great lengths to keep the Ancients' knowledge from falling into Goa'uld hands when the team discovers a second repository. The President replaces General Hammond with a civilian diplomat.

Anubis begins a systematic assault on Earth, and the planet's only hope of salvation depends on whether SG-1 can find the Ancients' mythical Lost City.

The fate of the galaxy hangs in the balance as Sam and Jacob search for the only weapon capable of stopping the Replicator onslaught. O'Neill leads a defense of the S.G.C., while Daniel squares off against Replicator Carter.