SG-1 discovers a planet where children are used to acquire knowledge for the entire population, then discarded.

SG-1 returns from a mission and discovers that metamorphic aliens have taken over the complex.

The members of SG-1 are imprisoned on a planet and become pawns in a war of ideology.

The members of SG-1 are used as forced labor in an underground alien facility after their memories are erased by the ruling elite.

Cassandra mysteriously falls ill, sending SG-1 back to her home planet -- where they uncover a dark Goa'uld secret.