Season eight of Stargate SG-1, an American-Canadian military science fiction television series, began airing on July 9, 2004 on the Sci Fi channel. The eighth season concluded on February 22, 2005, after 20 episodes on British Sky One, which overtook the Sci Fi Channel in mid-season. This was the first season of the show to have 20 episodes instead of 22, as well as the first to air concurrently with Stargate SG-1 spinoff series Stargate Atlantis. The series was originally developed by Brad Wright and Jonathan Glassner, while Brad Wright and Robert C. Cooper served as executive producers. Season eight regular cast members include Richard Dean Anderson, Amanda Tapping, Christopher Judge, and Michael Shanks. The eighth season begins with the SG-1 team trying to revive Colonel Jack O'Neill after the events of the seventh season. At the end of the two-episode season opener, Colonel O'Neill is promoted to General and assumes command of Stargate Command, while Major Samantha Carter is promoted to Lieutenant Colonel and assumes command of SG-1. The season arc centers around the growing threat and seemingly final defeat of the Goa'uld and the Replicators, races who were introduced in the first and third season of the show, respectively.
Having had the knowledge of the Ancients downloaded into his head a second time, Col. Jack O'Neill successfully modified a Goa'uld cargo ship to fly faster than any known vessel.
After learning from Dr. Daniel Jackson that the Goa'uld are en route to attack Earth, to confirm the existence of the devastating Ancient weapon, Stargate Command leader Dr. Elizabeth Weir arrests the Goa'uld system lords.
Aboard the International Space Station in Earth's orbit, Cosmonaut Anatole Konstantinov barely avoids being struck by part of Anubis' destroyed mothership as it passes under the station.
Five days to zero hour: Brig. Gen. Jack O'Neill is having a busy time managing his new duties as head of Stargate Command.
Dr. Daniel Jackson is in a farmhouse on another planet, recovering from serious wounds. Attending him is Leda. Three months earlier, SG-1 had visited this planet in the hopes of making new contact.
Goa'uld supersoldier drones have breached the gate room and have killed Brig. Gen. Jack O'Neill.
Teal'c, having finally been cleared to live off-base, settles in to his new neighborhood. His neighbors love him. He's quiet, and he has become a sort of protector of his community, having most recently defended a driver against three bullies.
The truth is out there, and Alec Colson, CEO of the global conglomerate and defense contractor Colson Industries, is going to make sure the truth goes out to the world.
Teal'c is ticked off. He and his mentor, Bra'tac, have just returned from the planet Ha'ktyl.
The stargate is gone! It vanished from Stargate Command right under the noses of the personnel on duty. Impossible? Not with Asgard beaming technology. Yet why would Earth's alien allies do that?
Unscheduled offworld activation: Lt. Col. Carter's IDC comes through, but it's an old one. A text message follows: "Send M.A.L.P."
With the Atlantis team unheard from since they left, a mission has been greenlighted to take the starship Prometheus to the Pegasus galaxy. Dr. Daniel Jackson wants in. Gen. O'Neill says no; Daniel is too valuable to risk.
Report from Tok'ra Intelligence: The war between Ba'al and the system lords has reached a critical stage. To escape Ba'al, Lord Ares is fleeing to a planet he once conquered, drained of Naquadah, then abandoned.
Brig. Gen. Jack O'Neill comes home to find treacherous former Vice-President Robert Kinsey in his living room. Kinsey tells O'Neill that he can help him take down.
Gen. Jack O'Neill finds an uninvited visitor in his home. Wielding a pistol (which is aimed at O'Neill's chest), Joe Spencer, a barber from Indiana, accuses O'Neill of ruining his life.
Lord Ba'al has brought the other Goa'uld system lords to the brink of surrender. Now he faces a threat even he cannot hope to survive: the Replicators. The machine species has been overpowering his ships throughout the galaxy.
Hidden in the ruins of the temple on Dakara is an Ancient weapon powerful enough to destroy the Replicators and all life in the galaxy.
With the planet of Dakara and the Ancient weapon now in the hands of the Free Jaffa, Anubis plans to reconquer the planet.
The world has lost one its unsung heroes: Catherine Langford, Daniel's mentor and one of the pioneers of the Stargate Program, has passed away.
In an alternate timeline, civilian scientists Samantha Carter and Daniel Jackson have followed the videotaped instructions of their alternate selves in Egypt, circa 3000 BCE.