Season synopsis
Contains spoilers for this season and earlier seasons.
Cameron Mitchell arrives expecting to join the SG-1 team whose example inspired him, only to find its members scattered among other assignments. General Hank Landry now commands the base, and Mitchell must assemble a team himself. Vala Mal Doran’s return offers a way to bring Daniel and Teal’c into a search for Ancient treasure beneath Glastonbury Tor. The discovery ties Merlin to the Ancients and yields a communication device. When Daniel and Vala use it, their consciousnesses enter bodies in a distant galaxy governed by the Ori.
These ascended beings demand worship and send Priors into the Milky Way to spread their religion, Origin. Daniel and Vala have inadvertently revealed the existence of the galaxy’s human populations to enemies of the Ancients. The new threat draws the team into a search for a weapon Merlin designed to oppose ascended beings, while the Priors’ influence reaches worlds still recovering from Goa’uld rule. Vala later contacts Earth from the Ori galaxy, reporting her unexplained pregnancy and a fleet being built for invasion. Her attempt to help resistance fighters destroy it fails.
SG-1 follows Merlin’s trail to a village called Camelot, but its discoveries do not give them a usable weapon before the invasion begins. Four Ori warships enter the galaxy and confront a combined defensive fleet drawn from Earth and its allies. The defenders’ weapons prove inadequate, and the battle devastates their ships, including the Russian Korolev. Vala watches from an Ori vessel as she goes into labor. The season closes during the defeat, leaving the scattered team’s survival and the invading fleet unresolved.