“Origin” is episode three of season nine of Stargate SG-1.
In the previous episode, “Avalon: Part 2”, using a device found in King Arthur’s tomb, Daniel and Vala had transported their consciousnesses to host bodies in another galaxy, where Vala’s host body had been burned to death for violating certain customs regarding the gods, the Ori, a group that Daniel believes are the Ascended descendants of the original race of Ancients. Vala’s host body was then brought back to life, as was she, by some sort of representative of the Ori with unusual powers.
The man, a Prior, is taking Daniel and Vala to meet the Ori. Another Prior has gone through a stargate to a Milky Way to proselytise the religion of the Ori. The alternative to accepting the Ori is death. In addition, a Jaffa leader who Teal’c does not trust has become the most powerful Jaffa and is visiting the SGC.
By accident, Daniel and Vala have revealed the previously unknown existence of a whole lot of humans to some very dangerous, and powerful, beings. Fire features rather heavily in their religion.
The story is still not over and continues in the next episode, “The Ties That Bind”.