In the Line of Duty

When the planet Nassya (P3X-382) falls under attack by the Goa'uld, Carter is possessed by a Goa'uld. When the Goa'uld is discovered, she claims to be Jolinar, a member of the Tok'ra, a legendary faction of rebel-Goa'uld opposed to the System Lords. When Jolinar is assassinated, she saves the life of Samantha Carter.