“Paradise Lost” is episode fifteen of season six of Stargate SG-1.
Maybourne, one of Colonel O’Neill’s least favourite people turns up at his house. He’s after a presidential pardon at the end of the current administration. In return, he’s going to give the stargate address to the planet with the Ancient weaponry cache on that Colonel Simmons was heading to when he stole the X-303 in “Prometheus”.
Unfortunately, they can’t enter the weapons cache, which looks like it may have belonged to another race that was part of the Ancient alliance, without Maybourne.
Maybourne double-crosses them and both he and O’Neill go through the portal – and end up stuck there. Wherever ‘there’ is. Now the others have to get them back before they kill each other – and they don’t know where they have actually gone.