The Goa'uld Hathor (one of the mothers of all Goa'uld), brainwashes the men of the SGC with pheromones, and nearly makes Jack a host to a larva conceived with Daniel. She flees after the unaffected women of Stargate Command retake the facility.

On their first visit to a new planet, SG-1 finds it subject to totally destructive volcanic activity and saves ten natives, the Tollan, a far more technologically advanced society. Their leader Omoc isn't grateful, nor interested in such a primitive race as the earthlings or any of the 'even more primitive' planets which are prepared to host them. Only one Tollan, Narim, shows an active interest in life on earth, especially in captain Samantha Carter and the cat Schrodinger she gives him, explaining his planet was destroyed after the Tollan supplied an unlimited energy source to a primitive neighboring planet which abused it for a cataclysmic weapon. Meanwhile, the White House authorized NID colonel Maybourne to take charge over the Tollan for military purposes, exactly Omoc's nightmare.

Samantha Carter becomes the host of a Goa'uld when she was trying to save the life of the previous host.

SG-1 inadvertently help a desperate criminal and are charged and sentenced as accessories to his crime. They are banished to a desolate, brutal penal colony and strike a deal with a powerful female prisoner to help them escape. But is this prisoner hiding something from them?

Alternate reality versions of Kawalsky and Carter are caught at Area 51 after coming through the quantum mirror.

An alien incursion takes control of the base.

The SGC send a MALP to a huge pyramid and inside they discover a crystal skull like the one Jackson's grandfather found many years before. SG1 visit the planet and whilst Daniel is looking into the eyes of the skull, as his grandfather did, an energy field envelops him. Teal'c fires his Zat at the skull, but Daniel has disappeared. Carter collapses and the team minus Daniel return to the SGC. Teal'c returns to collect the crystal skull, but will he be able to find Daniel?

The SGC is visited by a Tok'ra named Anise who brings some armbands used by the soldiers of a long extinct race, which are supposed to increase the abilities of the wearers. O'Neill, Carter and Jackson put the armbands on and it increases their physical strength, but it also causes them to make rash decisions. Can they get the armbands off before they cause their deaths?

When Teal'c is trapped in the Stargate buffer, the team must juggle the technical challenges along with personal, interdepartmental and diplomatic rivalries to rescue him in time.

On an alien planet, SG-1 discovers an inactive android is the only survivor of the destruction of her civilization. They bring her back to the SGC for study and manage to reactivate her. Things take a turn for the worse when she "makes" a replicator bug for Daniel.