Summit

"Summit" is the fifteenth episode of the fifth season of Stargate SG-1, and the 103rd episode overall.

Plot
Zipacna has summoned Osiris to his flagship. He complements Osiris' success in gaining a large army, and tells her of the situation among the System Lords, offering a position of great power. Osiris refuses to serve Zipacna, but Zipacna reveals that he is merely a servant of a Goa'uld who Osiris once knew well&mdash;Anubis. Daniel Jackson is sent by the Tok'ra to kill the Goa'uld System Lords, who are meeting to discuss the possibility of forming a new order. Since the deaths of Apophis and Cronus, the System Lords have been facing an unknown enemy of late, one which seems to be dispatching their armies with great ease. The Tok'ra see the meeting as an opportunity to kill all the System Lords at once, since the Tok'ra have recently developed a poison which is effective against Goa'uld symbiotes. It is an aerosol poison, making it relatively easy to use, and is non-lethal to non-blended humans. Daniel, because of his ability to speak Goa'uld fluently, is sent disguised as Yu's personal human slave, or "Lo'taur," with the idea of releasing the poison as soon as the System Lords have gathered.

However, the Goa'uld Zipacna is aware of the poison, and has sent a large attack force to the Tok'ra homeworld, where the rest of SG-1 is currently awaiting the results of Daniel's sabotage mission. The planet comes under attack, and the Tok'ra's stargate is rendered unusable by an incoming wormhole. The base shuts down power to remain undetected, but the attack force has more than enough Al'kesh to bomb the planet's surface indiscriminately. Portions of the base begin to crumble, and the base is in chaos. Lantash, who has been in a stasis chamber since the death of Martouf, is forced to blend with Lt. Elliot when his chamber is destroyed by falling rock. SG-1 decides to leave the underground base and take its chances on the surface, with Lt. Elliot barely alive as a result of a tunnel collapse. As they near the ring transporter, another section of tunnel caves in, blocking off their escape.

The conference of the system lords is delayed when a request is made, presumably by the mysterious enemy, to send his own representative to the council. When the representative arrives, she turns out to be Osiris. Daniel is taken completely off guard, and decides not to release the poison yet. He informs Selmak of the situation, but before he has a chance to respond, Osiris corners him, and reveals that she does indeed remember who he is.