Teal'c has returned to his home planet of Chulak to continue his work of turning the Jaffa against the Goa'uld who enslave them. His rebellion is well known; some respect him as a freedom-fighter, others despise his as the "shol'vah" -- the traitor who betrayed their god.
Teal'c's work on Chulak has never been more important. Since Apophis attacked and slaughtered many of their people ("Maternal Instinct"), many are more receptive to his ideas. He meets with two men -- Hakar and Rak'nor -- at night. Rak'nor is a Jaffa warrior with many followers. But Rak'nor betrays Teal'c, calling in a guard. The guard shoots Teal'c with a zat gun, rendering him unconscious. He is captured.
On Earth, Jacob Carter and the SGC receive a transmission from the Tok'ra through the Stargate. There is an important mission for them to undertake immediately: a transmission between the two most powerful Goa'uld -- Apophis, who now controls the army of Sokar("The Devil You Know"), and Heru-ur. The two will meet in the Tobin system to discuss an alliance.
The Tobin themselves are extinct; but their legacy includes a vast minefield surrounding their homeworld. The mines are programmed to target certain energy frequencies, including Goa'uld weapons fire. It is the perfect neutral ground for the Goa'uld to meet; if one fires, his ship will be assaulted by the large mines.
But the Tok'ra have come into possession of a Tobin technical manual for the mines, which they cannot entirely translate. It is based on ancient Phoenician, so Daniel can lend a hand. Jacob, Sam, Daniel and Jack set out in the Tok'ra cargo ship to reprogram one of the mines so that it will hone in on a specific frequency. When a Tok'ra operative on board Apophis' ship sends out the proper signal, the mine will be attracted to the ship and Apophis will believe Heru'ur is attacking him.
But the ultimate goal is not to destroy Apophis' mothership. Jacob believes that Apophis' next move will be to withdraw and gather his forces for an attack on Heru'ur's homeworld. All-out war between the two great armies is the goal. Their forces will be diminished, returning the balance of power to the collective System Lords -- which is preferable to one all-powerful Goa'uld.
Teal'c is dragged into a long, dark room, and chained. He hangs helplessly as a Goa'uld torturer, Terok, welcomes him. He tortures Teal'c with a pain stick while Rak'nor watches. Terok is recording the torture sessions for posterity; his goal is to break Teal'c, and make him say that he was wrong in turning against the gods.
Jacob and the rest of SG-1 arrive at the Tobin system, and transport one of the mines aboard. Carefully, Sam and Daniel discover how to open the access panel. Using the Tobin manual, Daniel instructs Sam on how to input the correct combination that will allow them to reprogram the mine. But the combination doesn't work; the mine begins a 5-minute countdown to destruction.
Teal'c continues to be tortured, and Rak'nor is shocked to see him endure it. He discovers that Teal'c would rather die and condemn his soul to eternal punishment than to acknowledge the Goa'uld are gods. Rak'nor is confused, but unsympathetic with the traitor.
In fact, he has a deep hatred for Teal'c. Years ago, Teal'c spared the life of Rak'nor's father after Apophis ordered him killed. His father became a believer in Teal'c's anti-Goa'uld philosophy when Teal'c left the service of Apophis, and he even seared off the gold seal from Rak'nor's forehead. But when Apophis returned to Chulak and attacked, Rak'nor's father and the rest of his family were killed. For this, he blames Teal'c.
Apophis and Heru'ur arrive in the Tobin system and discuss their alliance. They control the two largest armies of the Goa'uld, and together they can easily defeat the combined System Lords.
Sam and Daniel discover a discrepancy in the Tobin manual: there is no zero in the ancient Phoenician numerical system, but there must be a zero in the Tobin system in order for them to create such advanced technology as the mine. They alter the access code, and are able to reprogram the mine. It is launched back into space, as the cargo ship remains in stealth mode -- hidden from Apophis and Heru'ur.
Teal'c's painful torture is halted, momentarily. Terok has been unable to break him, and grows frustrated. Teal'c now finds himself dragged into Heru'ur's throne room. He is no longer on Chulak, he discovers, but on board Heru'ur's mothership. The Goa'uld offers him as a gift to Apophis to seal their alliance. Apophis accepts.
Terok is not finished with Teal'c yet. Knowing Apophis can revive his prize with a sarcophagus, the torturer takes a Goa'uld hand device and moves to kill Teal'c. But Rak'nor has been convinced by Teal'c's steadfast resistance to the torture. He renders Terok unconscious with the pain stick, and the two transport his body to Apophis' ship in Teal'c's place.
On board Apophis' vessel, the Tok'ra operative actives the beacon. The mine responds, hurtling toward the ship and exploding. Believing Heru'ur is attacking, Apophis does not withdraw as Jacob had expected: instead, he reveals an entire fleet of his ships, cloaked around him. Heru'ur knows that he is helpless, and his ship is quickly destroyed by Apophis. As the rest of the mine field collapses in on Apophis' ship, his fleet surrounds him -- sacrificing themselves so that he can escape.
A death glider emerges from the ship before it explodes: it is Rak'nor and Teal'c. They agree to rendezvous with Jacob and SG-1, who are relieved to learn that Teal'c made it out alive.
But the mission is a failure, with the worst possible result. With Heru'ur dead, Jacob's symbiote Selmak tells them, Apophis will easily absorb Heru'ur's forces into his own. He is now a greater threat than ever before.