When Sheppard's team encounter a culture with phase shift technology that keeps their entire population invisible - and immaterial - to the outside world, it looks like Atlantis might have found the perfect protection from the Wraith.
Doctor Carson Beckett finds himself in an uncomfortable situation when he becomes a patient in his own infirmary. After a disastrous mission, Beckett is brought back to Atlantis with a broken leg - and a bad case of amnesia.
Zelenka reluctantly finds himself aboard the Starship Apollo as part of Colonel Carter's drive to survey the area of space surrounding Atlantis' new planet.