Stuck on a Goa'uld ship, the SG-1 team must somehow thwart an attempt to destroy Earth.
Samantha Carter's body is taken over by what at first appears to be a Goa'uld, but eventually reveals itself to be a Tok'ra.
After assisting a stranger who turns out to be murderer on the run, the SG-1 team is charged as accomplices in his crime and banished to a rough penal planet where the strongest inmates rule.
The SG-1 team travel to a planet and find themselves locked into a virtual reality game which allows them to relive key moments in their lives and attempt to alter their outcomes.
During the exploration of a planet, the SG-1 team comes across a group of warriors they believe to be Jaffa, and Daniel becomes smiiten with its beautiful princess. While she attempts to make him her new king, the rest of the team is enslaved and forced to work in a mine.
Following the destruction of "Thor's Hammer" by SG-1, the team returns to the planet Cimmeria upon learning of a Goa'uld invasion and hopes to stave off the enemy.
While exploring a dead planet, SG-1 comes across an orb with an electromagnetic source, but upon returning with it to the SGC, the orb begins to create havoc by emitting an alien organism.
The son of Teal'c, Ryal'c, is kidnpped by Apophis and brainwashed to denounce his father, but when Teal'c, accompanied by the SG-1 team, goes back to Chulak to rescue him, he learns that much has changed.
Upon returning to Abydos, Daniel learns that his wife, Sha're, is nine months pregnant and that Apophis, the father, plans to use the baby as a host. Carter reconciles with her estranged father and learns he has cancer. Meanwhile, while in Washington to receive a medal of honor, O'Neill is approached by a reporter who plans to reveal all about the Stargate in an article.
Teal'c is bitten by a strange and deadly insect.
Samantha Carter has a dream in which she can see through the Goa'uld Jolinar's eyes, which leads her to accompany SG-1 on a mission to find the Tok'ra.
Samantha's dying father agrees to become a human host for the Tok'ra Selmak, whose own host is dying.
The SG-1 team travels to a planet protected by strange spirits, where the SG-11 team has disappeared.
When SG-1 attempts to recover a weather-control device known as the Touchstone, it is learned the device was stolen through the use of a second Stargate on Earth previously believed to be deactivated.
O'Neill briefly gains the wisdom of the alien creators of the Stargates.
While rescuing the SG-10 team, the SG-1 crew is pulled in by a black hole.
The SG-1 discover and fall prey to a Goa'uld body-swapping invention which leaves Daniel clinging to life in the body of a dying old man and causes O'Neill and Teal'c to swap bodies.
The SG-1 offers sanctuary to old nemesis Apophis, who is being chased by Goa'uld gliders and claims to be dying. It is soon learned that a mighty Goa'uld named Sokar, the god of death from Egyptian times, has come for Apophis and will destroy everyone around him unless his intended capture is handed over.
While on a mission to retrieve a crashed UAV plane, the SG-1 team ends up on a planet where life is more simplified than Earth, and unwittingly sets forth a virus that could destroy the civilization of its inhabitants.
A young boy arrives at the SGC with his mother, a member of an invisible race which was destroyed by the Goa'uld and in turn plans to destroy all humans and other potential Goa'uld hosts.
When the SG-1 team ends up back in 1969 due to a solar flare, they land at a secret military base where a note carried by Carter from General Hammond is discovered by a young Lieutenant Hammond. Realizing the team is from the future, Hammond sets them out for New York to find the one person capable of helping them get home.
O'Neill wakes up and finds that he has been cryogenically frozen for almost 80 years as have the other members of the SG-1. When he is strangely asked to help the unfamilar crew with information on how to defeat the Goa'uld, O'Neill soon learns he and the others may be part of a Goa'uld setup.