The Daedalus arrives and the two hive ships are destroyed. Atlantis seems saved, then Zelenka detects 12 more ships. Ford seems changed after a fall in the water.
The team discovers a planet where the Stargate is kept on a prison island to keep the Wraith satisfied. Their magistrate is willing to trade a rare mineral.
The team discover an Ancient project to create the ultimate power source. McKay thinks he can finish it. Ronon finds out he is not the only surviving Satedan.
The team find a hidden Wraith girl, cared for by a man with a serum that he claims can satisfy her hunger. Beckett wants to perfect a retrovirus that can turn Wraith into humans.
Sheppard is infected with the Wraith retrovirus and slowly turns into an Iratus bug. To provide a treatment, stem cells must be retrieved from one of their eggs.
The teams discovers a ridge that can only be entered through a door. Sheppard gets pulled in by a field. McKay discovers time goes very fast behind it.
The team discovers two life pods with a dying woman and man in them. When they are opened, Weir gets imprinted with the mind of the woman. She asks a special favor.
While Teyla and Ronon investigate the apparent death of Major Lorne, the Genii Ladon Radim contacts Atlantis. He wants to trade a ZPM for weapons supplies.
Michael Kenmore, a new lieutenant, awakes in the infirmary and doesn't remember a thing. The other expedition members are very concerned about his well-being as he seems different.
The hive ship approaching Atlantis is Michael's. He wants a trade: the retrovirus for not revealing the secret of Atlantis and insights on Wraith technology.