20 episodesFirst aired 15 July 2005
As the Wraith threat intensifies, the team strives to find ways to defend Atlantis and the Pegasus Galaxy from impending invasion. Key episodes focus on breakthroughs in ancient technology, dangerous alliances, and a desperate search for a means to stop their enemies once and for all.
E1Jul 200542m
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.
E2Jul 200544m
The Daedalus is infected by a Wraith computer virus, while members of the expedition hope to return to Earth.
E3Jul 200542m
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.
E4Aug 200542m
A run-in with a Wraith Dart leaves the consciousness of a precocious Atlantis security officer trapped in Dr. McKay's mind.
E5Aug 200542m
The Atlantis team finds a culture that lives in relative safety from the Wraith, because they hand over their criminals to the Wraith -- and crash-land in the volatile penal colony.
E6Aug 200544m
McKay puts the team at risk when he tries to perfect unfinished Ancient technology that wiped out a civilization. Ronon Dex discovers that he is not the lone survivor from his world.
E7Aug 200544m
The team discovers a young Wraith girl who has been raised by a human, and is in hiding from the people of her human village in fear of her life.
E8Sept 200542m
Colonel Sheppard begins to undergo a disturbing physical transformation after being exposed to Beckett's anti-Wraith drug.
E9Sept 200544m
When the team finds an Ancient warship adrift on the edge of the galaxy, its crew still alive, Colonel Sheppard enters their virtual reality stasis to communicate with them.
E10Sept 200544m
The team is captured by the missing Lieutenant Ford, who is now leading a group of young men who are taking the Wraith enzyme -- and who wants the team's help in a suicide attack against a hive ship.
E11Nov 200544m
Colonel Sheppard and his team find themselves prisoners of the Wraith following Ford's attack on a hive ship. Dr. McKay goes to great lengths to help them.
E12Nov 200544m
Sheppard finds himself on a planet where time passes more rapidly, with no way to contact his team or return to Atlantis.
E13Dec 200544m
When an operative of the Trust plants a bomb in Atlantis, the team must find a spy within their own ranks before the Wraith arrive and discover the city.
E14Dec 200544m
When Dr. McKay is trapped underwater in a sinking Puddle Jumper, his only chance for survival may be an hallucination of Samantha Carter.
E15Dec 200544m
The team finds a world that possesses Ancient defense technology, where Colonel Sheppard finds himself a pawn in the rivalry between the heirs to the throne.
E16Jan 200644m
The team discovers two pods that contain the minds of alien beings, who take control of Weir and Sheppard's bodies to continue their personal war.
E17Jan 200644m
After a team from Atlantis goes missing, the expedition finds itself in the middle of a Genii coup.
E18Jan 200644m
An amnesiac young Lieutenant in Atlantis suffers from disturbing nightmares that he is a Wraith, only to make a shocking discovery about himself.
E19Jan 200644m
Sheppard's team meets a civilization about to be destroyed by a super-volcano, and is trapped there when the Stargate is destroyed during the evacuation.
E20Jan 200644m
Michael and his Wraith faction arrive at Atlantis to propose an alliance, hoping to use the retrovirus to transform their Wraith enemies into prey.
