Stargate SG-1: Gift of the Gods (SG1.1)

"Years ago, I'd have felt uncomfortable with a Beretta in my hands. But not now..."

Doctor Daniel Jackson wakes up on the floor of his SGC lab, with no memory of what happened or how he got there. With him is Lt. Hunter of SG-12 - the team that should have accompanied SG-1 on their mission to P2K-797. But now, here they are, back on Earth with the whole of Stargate Command incapacitated around them.

So what happened? Why can no one remember? And why is the Stargate apparently connected to an alternate reality?