Teal'c and O'Neill are transported to an underground cage designed by the Asgard to protect an alien world from the Goa'uld.

SG-1 tracks down Catherine Langford's fiancee, who took the first Stargate trip in 1945, and discovers an ancient meeting hall that may hold the secrets of the universe itself.

The banished Goa'uld Hathor is found in an ancient sarcophagus Earth, and takes over the S.G.C. with hopes of raising a new army against the System Lords.

A mysterious affliction wipes out the entire population of a planet, plus an SG team -- except for one young girl. Carter befriends her, but learns that she is being used by the Goa'uld.

SG-1 locates the Tok'ra, a Goa'uld resistance movement who oppose the System Lords, and attempt to form an alliance. Jacob Carter's cancer brings him near death.

While SG-1 tries to form an alliance with the Tok'ra, a spy betrays the rebels to the Goa'uld. Jacob Carter finds that the Tok'ra may be his only hope of survival

SG-1 is accused of stealing an important weather-controlling device, sending a primative planet into chaos. The team discovers that Earth's second Stargate is being misused.

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

Daniel comes face to face with the Ori, a fiery race of beings who demand the worship of mortals. Elsewhere, Stargate Command encounters the first Ori missionary in our galaxy.

Samantha Carter returns to Stargate Command when the Ori seize control of a planet, using an expanding force field to gain a foothold in our galaxy.