 Food supplies on Atlantis are dwindling and the team visit the Genii. Teyla has traded with this primitive culture before, but their chief Cowen seems reluctant to trade a large portion of their food reserves. Only when Sheppard shows them they can clear land easily by using C4, they are suddenly interested. Later McKay detects unusual neutron radiation. He and Sheppard find a strange hatch, that leads to a technologically advanced city. They discover the Genii aren t as simple as they appear to be. Cowen tells they are building a nuclear weapon to attack the Wraith and they expect to have at least several years until the next culling.