Stargate SG-1 - Season 3 Episode 14 -

After a vain search for the Harsesis boy on an unexplored planet, SG-1 is told there is a chemical leak and gets sedating injections in the infirmary. In fact star-base has been taken over by body-snatching aliens, as Teal'c and Sam discover, who are immune because of his symbiont and her Jolinar-remnants. Teal'c is captured while giving Sam the chance to escape; she meets with Colonel Harry Maybourne, who alas believes and brought the alien-possessed Jack and Daniel, who claim it's paranoia caused by the leaked chemical; during a flight back, Sam is able to see ...