An alien artifact transports Daniel to an alternate reality, where he is not a part of the Stargate program and the Goa'uld -- led by Teal'c -- are invading Earth.

SG-1 escapes through the Stargate before it is shut down, and learns that Daniel's alternate reality vision is true: Apophis is moving to attack Earth from above. The team must stop Apophis and his son, Klorel, who inhabits the body of their friend Skaara.

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

Jackson becomes addicted to the effects of a Goa'uld sarcophagus, and falls for the planet's manipulative princess.

SG-1 discovers an ancient artifact that takes O'Neill and the S.G.C. hostage.

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.

O'Neill becomes the unwilling receptacle for a library of alien knowledge.

SG-1 discovers an elderly man known for developing technology to fight the Goa'uld. Daniel is tricked into switching bodies with the man, Ma'chello, who believes he is "owed" for all the good he has done.

The Tollan put Skaara and Klorel on trial to determine who will control the host body.

After a meteor strike buries the Stargate, O'Neill finds himself stranded on a planet with no hope of rescue.

SG-1 helps to evacuate the Tok'ra to a new base -- but matters are complicated when a spy reveals their location to Apophis. The team attempts a daring plan to take out the Goa'uld's powerful fleet.