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.
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.
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.
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.
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.
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.
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.
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.
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.
