Sgt. Harriman is on duty when the Stargate . . . disappears. Security tapes reveal it was an Asgard teleport beam. Teal'c is stranded off world and goes to the Alpha Site. Sam determines they were getting anomalous readings when a technician was present – a technician who has disappeared without a trace, that they conclude is tied to the Trust. Teal'c returns to the planet where he was meeting with Jaffa rebels and finds them all dead except for one – M'zel, who recently returned to the planet.
SGC tracks the tagging signal of the teleportation device to a warehouse containing nerve gas and missiles, and an operative who shoots back and breaks open the nerve gas canisters. But the gas is harmless and it turns out it is symbiote poison. The operative has an Area 51 badge and Daniel and Sam go there and meet with a Dr. Bricksdale to obtain the remote teleport-bracelet Osiris used. Teal'c determines that the Jaffa were poisoned with the Tok'ra poison and other planets have been attacked as well. M'zel suspects the Tok'ra - he and Teal'c prepare to contact an undercover operative, Zarin, by letting themselves get captured and brought before her.
The teleport bracelet checks out but Bricksdale is working with the Trust and is followed. The Trust operative Hoskins tries to escape but Sam zats him and finds a teleportation unit – she is beamed up with Hoskins and stunned. Daniel interrogates Bricksdale who reveals what he knows – that he accidentally beamed aboard to Osiris' orbital ship until the Trust contacted him. Teal'c and M'Zel meet with Zarin, who is nervous about meeting with them and blowing her cover.
The Trust members reveal to Sam that they are planning to wipe out the Jaffa, whom they perceive as enemies along with the Goa'uld, and they target the planet where Teal'c is. Zarin, Z'Mel, and the other Jaffa die, although Teal'c is immune since he lacks a symbiote. The Prometheus conducts a search for the cloaked ship while Daniel gets Bricksdale to activate the teleportation remote bracelet and beams up. He sabotages the cloak but is captured. The Prometheus gets a lock but Jack chooses to give Daniel the time he presumably needs.
The Stargate opens just as the Trust prepares to kill Sam and Daniel, using the distraction to start a fight to escape. Teal'c is trying to return and Daniel tells him to come through. Teal'c kills Hoskins but the female Trust member, Brooks starts to take the ship into hyperdrive. The trio signal the Prometheus for teleportation of themselves and the Gate.
Later a device to jam locator beacons is installed near the Stargate to prevent further teleportation. The Trust is still out there with enough Tok'ra poison for any number of operations.