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.

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

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.

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.