A new Stargate team embarks on a dangerous mission to a distant galaxy, where they discover a mythical lost city -- and a deadly new enemy.

The Atlantis base is threatened when the team discovers that an alien entity is in the city. McKay's experiment with alien technology goes awry.

After a series of run-ins with the Wraith, the team begins to suspect their Athosian allies of having a spy in their midst.

Sheppard and the team visit a world where no one is over 24 years old -- because of a ritual suicide practice they believe keeps the Wraith at bay.

The team searches for a valuable Zero Point Module rumored to be hidden on the planet Dagan -- but their new allies have motives of their own.

With a brief opportunity to send a data transmission to Earth, members of the Atlantis expedition compose video messages home to their loved ones.

Plagued by terrifying nightmares, Teyla begins to recall a time when she and her father were captured by the Wraith and subjected to disturbing experiments.

With a group of Wraith hive ships on the way to Atlantis, the team searches for a place to flee and a way to destroy the city. McKay leads a team to try and activate the Ancients' orbital weapons platform.

All hope seems lost, until Colonel Everett arrives suddenly from Earth. He is determined to defend the city until the arrival of a ZPM, brought by a new ship.

The Daedalus arrives to defend Atlantis from the Wraith onslaught, but it may not be enough when the team discovers that an even larger armada is on the way.

Sheppard and his team attempt to locate Lieutenant Ford, only to find themselves captives of a former soldier who is being hunted by the Wraith.

A run-in with a Wraith Dart leaves the consciousness of a precocious Atlantis security officer trapped in Dr. McKay's mind.