Ep 6. Abyss

In season 6 episode 6 of Stargate SG1 titled "Abyss", the episode starts with Colonel O'Neill being kidnapped by the Goa'uld System Lord Ba'al. Ba'al brings O'Neill to his stronghold, where he plans to torture him for information about the Tok'ra. O'Neill is subjected to a form of torture known as "Abyss," where the victim is slowly killed and then revived repeatedly, causing immense pain.

Meanwhile, the SGC is trying to track down O'Neill's whereabouts and sends a team to search for him. During their search, they come across a Goa'uld laboratory that is experimenting on humans. They free the captive humans and find out that the Goa'uld are trying to create a super soldier.

Back in the Abyss, O'Neill is hallucinating and having vivid nightmares, causing him to question his sanity. Ba'al tries to convince him to give up the location of the Tok'ra base, but O'Neill refuses to talk, despite the immense pain he is enduring.

As the team continues their search, they come across a Jaffa who is willing to help them find O'Neill. Together, they make their way to Ba'al's stronghold, but once they arrive, they realize they are vastly outnumbered.

Back in the Abyss, O'Neill is visited by a familiar face - his former enemy, Apophis. Apophis offers to help O'Neill escape, but O'Neill is suspicious of his motives.

As the team engages in a firefight with Ba'al's Jaffa, they are eventually able to breach the stronghold and rescue O'Neill. But they soon realize that he is not the same man they knew before. O'Neill has been changed by his experience in the Abyss and is struggling to deal with the trauma he endured.

The episode ends with O'Neill seeking solace in the company of his teammates, but it is clear that he will never be the same person as before. The events he endured in the Abyss have left an indelible mark on him, and he will have to find a way to live with the scars both physical and a bit psychological, inflicted upon him for a long time to come.