 In the third-season episode "The Return", the Athosians are asked to leave Lantea by a group of surviving Ancients reclaiming Atlantis from Earth.The Athosian population is subsequently found to have disappeared from New Athos in "Missing".The search for the missing Athosians and their fate at the hands of the rogue Wraith Michael contributes to a major plot arc near the end of the fourth season.