02E02 - In the Line of Duty

During a visit to the Nasyan planet, under the first goa'uld attack in centuries, a victim's breath given mouth-to-mouth infects Sam, at first unnoticed. Soon her behavior changes, more military and assertive, and she seems to suffer from amnesia. Cassie senses immediately Sam really hosts a goa'uld, which is confirmed by her attempt at gunpoint to escape via the star-gate, and since the aliens now seem able to enter via small skin wounds as in her throat, Dr. Fraser points out there may be others in the base. Sam is jailed but allegedly hosts Jolinar, a 'Tok'ra' or good, anti-warlord goa'uld underground rebel, being chased by an 'ashrak', a goa'uld hit man, who has already started his deadly assignment on earth...