The Tok'ra arrive with a mission for Daniel: to infiltrate an upcoming summit of the Goa'uld system lords and assassinate them all by releasing a poisonous gas that's fatal to Goa'uld symbiotes. The rest of the team wait at the new Tok'ra home base, only to become trapped when the planet is attacked by Zipacna, while Daniel's mission is complicated by the unexpected arrival of Osiris.
First appearance of Ba'al and first direct reference to Anubis.
"Summit" provides examples of the following tropes:
- Back for the Dead: The Tok'ra Aldwin, last seen in season 3.
- Be Careful What You Wish For: Before the mission, Elliot states that he's looking forward to finally seeing some action; by the end of the episode all his teammates are dead, he's mortally wounded from having a tunnel collapse on top of him, and he has a Tok'ra symbiote in his head.
- Chekhov's Gun:
- Daniel uses a modified version of the Reol venom on Yu.
- Towards the beginning of the episode, Ren'al shows Carter a tank where the symbiote Lantash is being kept in stasis; after the tunnels are bombarded by Zipacna's forces, the tank is destroyed and Lantash goes into Lt. Elliot in order to save them both.
- Cliffhanger: The episode ends with O'Neill, Carter, Teal'c and the severely wounded Elliot trapped in the Tok'ra tunnels as Zipacna bombards them from above, while Daniel is on a space station with a handful of angry system lords and his cover about to be blown by Osiris.
- Continuity Nod:
- As promised, Lt. Elliot has been officially assigned to an SG team and embarks on his first mission.
- Ren'al reintroduces Aldwin, pointing out that the members of SG-1 already know him after he assisted Teal'c in rescuing them from Netu.
- Ren'al tries to assure Carter that every effort was made to save Martouf after the events of "Divide and Conquer".
- Deadly Gas: The Tok'ra have devised a chemical weapon which is harmless to humans but utterly fatal to symbiotes; they plan to have Daniel release this at the summit in order to wipe out the system lords.
- Gender Bender: Zipacna muses on Osiris's decision to take a female host.
- Genocide Dilemma: Averted for the most part, as Jacob reveals that the long term plan for the Tok'ra is to wipe out all the Goa'uld using the symbiote poison. He does struggle a little more when Daniel points out that this will also result in the deaths of thousands of Jaffa, but even then he seems to consider it an acceptable loss.
- The Infiltration: Daniel infiltrates the Goa'uld summit by posing as Lord Yu's personal slave.
- Lie to the Beholder: The Reol venom works this way, causing Yu to see Daniel as his trusted slave once he's been injected with it. Unfortunately, he doesn't count on Osiris showing up, and she is able to recognize him instantly. So Daniel simply doses Osiris too.
- Mercy Kill: Jacob invokes this when Daniel shows some hesitation over the fact that the hosts of the system lords will also die if the assassination goes as planned, pointing out that most of them will be hundreds if not thousands of years old after going in the sarcophagus so many times.Daniel: So we're doing them a favor?
Jacob: In many ways, yes.
- Neck Snap: Aldwin dies this way, after he lands awkwardly on his head after getting thrown by the blast wave of an explosion.
- I Need to Go Iron My Dog: O'Neill's excuse when Aldwin tries to rope him into the orientation tour alongside SG-17:O'Neill: Thank you, Aldwin, but I have to go help Teal'c... wait for Daniel.
- The Neutral Zone: The Goa'uld summit takes place on an abandoned space station in neutral space where no weapons are permitted.
- Not So Different: For all their emphasis on equal partnership in contrast with the Goa'uld, Carter accuses the Tok'ra of caring more about the symbiotes than the human hosts after she find out that they chose to remove Lantash from Martouf and put the symbiote on life support, despite the slim possibility that it could still have healed Martouf's injuries.
- Not-So-Harmless Villain: Zipacna was pretty laughable in his first appearance, but here he manages to totally obliterate the Tok'ra base, resulting in the deaths of several Tok'ra and SGC personnel.
- The Only One: Despite the fact that assassination and subterfuge are not exactly his specialties, Daniel is the only person qualified to infiltrate the system lords' summit, as it requires a human who is fluent in Goa'uld.
- Oh, Crap!: Osiris when (s)he learns that the Zipacna serves Anubis.
- Out of the Frying Pan: Discussed by Jacob and Jack. Jacob complains that Stargate Command's series of killings of major Goa'uld (at this time, Ra, Hathor, Sokar, Heru'ur, Cronus, and most recently Apophis) keeps creating power vacuums that even worse Goa'uld invariably step in to fill. This culminates in the rise of Anubis, a partially ascended Goa'uld who was banished by the others millennia before. Jack retorts that "at least we're doing something", pointing to the fact that Earth has made more progress in actually taking down the System Lords' empire than the Tok'ra had in two thousand years.
- Passive-Aggressive Kombat: Much of the interaction between the system lords, especially where Ba'al is involved.
- Poison Ring: Loaded with Re'tu toxin.
- Sarcasm-Blind: Aldwin.Aldwin: Are you interested in Tok'ra engineering?
O'Neill: Oh... interested doesn't quite describe how I truly feel.
Aldwin: Well, you're welcome to join us.
- Spanner in the Works: Osiris's appearance at the summit complicates Daniel's mission on two separate fronts; on the one hand, she recognizes him and could blow his cover with the other system lords at any moment, while on the other hand his personal attachment to Sarah makes it that much harder for him to release the poison.
- Suspiciously Similar Substitute: Ren'al replaces Anise/Freya as a somewhat distant female Tok'ra scientist.
- Teeth-Clenched Teamwork: Osiris and Zipacna make no secret of the fact that there's no love lost between them, despite the fact that they're both in the employ of Anubis and so ostensibly on the same side.
- Try Not to Die: Yu says a variation on this to Daniel as they enter the summit.Yu: Do not make me look foolish by allowing yourself to be murdered.
- Who's on First?: Yu's a character involved in this episode, so naturally...Jacob: Yu will be among the system lords attending the meeting.
Carter: I thought you said he was going in as a slave.
Jacob: The system lord Yu.
Carter: ...Little joke there.