Season 2 Episode 14 - Touchstone

SG-1's mission is to return to PX7-941, or Madrona as the inhabitants call it, to study the effects of, and technology behind the "Touchstone" device. However, SG-1 is accused of stealing this artifact by the Madronans. They claim "Touchstone" has been taken by a group of people dressed in SGC uniforms who came and went through the Stargate leaving the inhabitants without any protection from the planets deteriorating cilmate. As SG-1 trys to locate the device they uncover a sinister government agenda.