When powerful aliens come through Earth's Stargate, Colonel Jack O'Neill returns to Abydos to retrieve Daniel Jackson.

Major Kawalsky is possessed by a Goa'uld, and the SGC must find a way to remove it without killing him.

An alien civilization is forced to reconsider their views on women when Carter rebels against their social customs.

Members of SG-1 become infected with an alien virus that turns them into primitive beings. Dr. Fraiser must find a cure to save the team.

SG-1 must stop a renegade Stargate commander, who has gone mad and set himself up as a god on an alien planet.

During an off-world assignment, Jack is struck down by energy from a blue crystal... which creates a duplicate of him.