“Summit” is episode fifteen of season five of Stargate SG-1.
Osiris, the Goa’uld who inhabited a former colleague of Daniel’s and escaped in “The Curse”, meets Zipacna aboard his ship. The latter and is told that Osiris serves a much more powerful Goa’uld, and that he should join too. I had a feeling that Anubis was the mystery Goa’uld mentioned in “Between Two Fires” – I have seen some of the following episodes before.
There is a summit being arranged by the Goa’uld, and the Tok’ra want Daniel to infiltrate the meeting as a human slave, so that they can kill all the System Lords. Daniel agrees, and the Tok’ra use a chemical derived from that seen in “The Fifth Man” so that he can pass as someone else. Neither Zipacna nor Anubis are at the meeting though, and the other System Lords are being attacked by Anubis, although they do not know it. Osiris attends as Anubis’s emissary.
Lieutenant Elliot, from “Proving Ground”, accompanies them on the mission to the Tok’ra. Ba’al, quite probably the most interesting of all the villains in the series, also makes his first appearance.
The story does not conclude in this episode, but in the next episode, “Last Stand”.