On a mist-covered planet, McKay is puzzled by the strange energy readings and discovers that the Stargate can draw power from the very atmosphere itself – enough energy to create a wormhole back to Earth. They move the control crystal from Atlantis to the planet's gate, but it will be a one-way trip as they don't know if SGC has a Z.P.M. to let them come back.
Weir gives them the go ahead and they open the gate and establish radio contact. SGC tells them that the Asgard have rigged Prometheus with hyperdrives powerful enough to bring them back to Atlantis in a month. Weir, Ford, McKay, and Teyla go on through and are greeted by General Hammond. During their initial briefing, Hammond expresses the Pentagon's concerns about the Wraith and recommends they abandon the Atlantis outpost – Weir is strongly opposed and Hammond takes heeds her counsel.
Weir goes home to visit her boyfriend Simon and McKay returns to his empty apartment, while Sheppard takes Teyla on a shopping spree. But Sheppard starts to feel something is wrong, Weir begins to wonder about Simon, and even McKay realizes something is amiss when a hot woman starts hitting on him. Hammond then notifies Weir there was an accident on Prometheus and they can't use it to go back. McKay comes up with a plan to create a micro-link to the planet and use its energy to establish a full wormhole. Meanwhile Ford is transferred to a new assignment and Hammond announces that Weir will not go back to Atlantis and a military presence will be established and she's been relieved of command.
Meanwhile, Sheppard has figured a few things out and soon realizes anything he imagines happens – his dead friends show up for a visit. Weir, McKay, and Ford also start to put things together as they each realize they are trapped in a personal illusion. "Hammond" reveals to Weir that he is an energy-entity and they all find themselves in an illusion of the Gate room.
"Hammond" informs them that they were in separate realities (with Teyla sharing Sheppard's, since she has no memories of Earth), and he lets them have the chance to share a "fabrication." They refuse the alien's offer, and he states that they must be rendered helpless since the Stargate drains energy from the "mist," which are the aliens. Weir promises that they will not return and "Hammond" reads their minds to confirm their sincerity. They wake up and find themselves back on the planet, and they leave in peace.