Farscape S04E02 - What Was Lost Part I: Sacrifice

Elack arrives at a planet and Crichton, Chiana and Rygel are reunited with D'Argo and Jool who are at an archaeological site run by Jool's people, the Interions. The purpose of the dig is to find a missing probe which might reverse the dangerous atmosphere of the planet. But things take a turn for the worse when Peacekeepers led by Grayza land on the planet.