The SG-1 team attempt to rescue Teal’c’s son, who has been kidnapped and brainwashed by Apophis. Teal’c learns disturbing news about his wife.

Teal’c is infected with deadly venom from a giant insect, and begins a terrible transformation. When he escapes the S.G.C., SG-1 must find him before Colonel Maybourne does.

SG-1 locates the Tok’ra, a Goa’uld resistance movement who oppose the System Lords, and attempt to form an alliance. Jacob Carter’s cancer brings him near death.

Carter is possessed by a Goa’uld who claims to be an enemy of the System Lords.

SG-1 is put on trial and exiled to a prison world, where a woman maintains a strange control over her fellow prisoners.

With SG-1 trapped on Klorel’s ship, it seems that Earth is doomed as the Pyramid Ships prepare to destroy Earth.