 Stargate Command discovers a Goa uld Ha tak in Earth orbit. Exploring, they discover it is the ship where Anubis briefly imprisoned Thor. At some point, Anubis  forces set the self-destruct and abandoned the ship, but something has halted the destruction and brought the ship to Earth. Jacob/Selmak opens the computer core so the team may learn more. Then the ship begins to descend towards Earth. SG-1 must discover what s going on before the destruction of the Ha tak threatens Earth. And hopefully, escape the doomed ship themselves.