Abyss

Abyss is the sixth episode of the sixth season of Stargate SG-1.

Plot
On an unknown planet, a man and a woman run away from a number of Jaffa. The man, a Tok'ra, tells the woman to hide, while he tries to reach the Stargate. However, before he can activate it, he is shot down with a Staff weapon and the symbiote leaves his body. The host, Col. Jack O'Neill, is captured and later wakes up in a Sarcophagus. He is watched by a strange man in the shadows.

At Stargate Command the Tok'ra Thoran visits and tells General Hammond and SG-1 that the Tok'ra Kanan, (who had blended with a comatose O'Neill in the previous episode to save him from an Ancient disease) left them on his own and the SG-1 thinks that he might have done this without O'Neill's approval, which angers Thoran. He later discusses Kanan's behavior with SG-1 but refuses to give them mission reports from Kanan. Because of this he isn't allowed to leave the base. Gen. Hammond and SG-1 explain that they only want the mission reports so that they can attempt to find O'Neill, so he finally agrees to give them to SG-1. The team then tries to find out why Kanan left, but cannot find any clues.

Meanwhile in Ba'al's base, O'Neill is brought into a room and pinned to a wall with some kind of gravity device. He is then questioned by Ba'al who tortures him with knives, "dropping" them into the gravity field, and thus into O'Neill, who soon dies. He is then reanimated via the Sarcophagus and brought into a cell. After seeing a woman at the top/end of his cell (a similar gravity device to the used by Ba'al to torture O'Neill redirects the gravity in his "cell" 90°, turning it into an oubliette when activated) he is visited by the ascended Daniel Jackson. Although O'Neill first thinks that he is a delusion, Daniel manages to convince O'Neill that he is real. They start to talk about what has happened to O'Neill and why he is imprisoned. Eventually, Jackson offers to help him ascend but O'Neill wants more information, which Daniel cannot give him. Instead, O'Neill wants Jackson to help him escape but he is unable to do this due to the Others' policy of non-interference.

They are interrupted when two guards appear to take Jack back to Ba'al. O'Neill is again questioned by the System Lord, this time being tortured by acid. After some time, O'Neill finally gives him the name of his symbiote. Ba'al heals O'Neill once more and sends him back to his cell. O'Neill is later brought back into his cell where he again sees the woman from before. Daniel appears shortly thereafter and they continue their discussion. While Daniel tries to explain to him what a person he is, O'Neill gets angry with Daniel's refusal to interfere. Jack is taken away once again for another torture session.

Back at the SGC, Major Carter points out that during Kanan's mission to get information about Ba'al's base, the Tok'ra used the System Lord's lo'taur (his personal slave) to get the information. She concludes that perhaps he had an affair with the female lo'taur and that he wanted to rescue her, using O'Neill's body to do so while he still had the chance. They tell Hammond about what they discovered, but he won't allow a rescue mission since Ba'al's base is a veritable fortress.

Back in Ba'al's base, O'Neill sees the woman again while being tortured by Ba'al. O'Neill can't answer Ba'al's questions but the System Lord nevertheless tries to get the information. O'Neill is later brought back to the cell where he nearly breaks down, this time Daniel does not appear to comfort him. He is soon questioned again but his mind is too weak to give clear answers and he only mumbles Daniel's name.

At SGC, Teal'c, after his kelno'reem during which the ascended Daniel has lead him to understand that they would be able to rescue O'Neill if they only had a Goa'uld mothership, so they make a temporary alliance with the System Lord Yu and give him the plans of the base so that he can destroy its power generator.

Back in O'Neill's cell, Daniel once again visits O'Neill, explaining his absence as having had something to do elsewhere ie visiting Teal'c in his meditation, but the Colonel is too weak to fight on. However Daniel, confident in Teal'c and the rest of the SGC's abilities, tells him that it will soon be over but their conversation is interrupted by explosions. It turns out that Yu is attacking, giving O'Neill the chance to flee. He finds Ba'al's lo'taur (the woman he had seen many times previously) and they both escape. He later wakes up in the infirmary of SGC, where he thanks his friends. After they leave, Daniel appears and they have a short discussion. Daniel leaves just before Carter returns.