An international team of scientists and military personnel discover a Stargate network in the Pegasus Galaxy and come face-to-face with a new, powerful enemy: The Wraith.

With the Ancients' city of Atlantis discovered in the Pegasus Galaxy by Stargate Command, Dr. Elizabeth Weir and Major Sheppard lead a scientific expedition to the ancient abandoned city.

Once there, the team not only find themselves unable to contact Earth, but their explorations unexpectedly reawaken the Ancients' deadly enemies, The Wraith, who hunger for this new prey. Now with the help of newfound local allies like Teyla Emmagan, the Atlantis Team sets about to uncover their new home's secrets even as their war of survival against the Wraith begins.