Unfortunately, the cast had to find out about it along with ... There was a canceled "Stargate" movie that would have brought all of the shows together, but that never came to pass.

For everyone who's still figuring it out.

The Stargate team goes to see Ba'al, the last of the System Lords, being extracted from his host. All of a sudden, Tealc, Vala and all of their allies start to vanish. Later Carter, Daniel ...

They find a land that recalls Egypt and humans in a primitive culture that worship and are slaves to Ra, the God of the Sun. But soon they discover the secret of the mysterious "stargate".