Coup D'etat

"Coup D'etat" is the seventeenth episode of the second season of Stargate Atlantis.

Synopsis
A call from some rogue Genii forces the team to reevaluate the two cultures' relationship, although not everything has changed.

Plot
Atlantis receives an emergency call from an off-world team on M1K-177 only to find them dead, having been burned in a fire. Shortly after this, Atlantis is contacted by Ladon Radim, a member of the Genii strike force, with the prospects of a new ZPM in exchange for weapons to orchestrate a rebellion and overthrow Cowen, the current leader of the Genii. After informing Cowen of this plan, Atlantis decides to raid Ladon's base. Ladon sends a few Genii civilians, including his sister Dahlia, all of whom are later discovered to be afflicted by terminal radiation poisoning. Lieutenant Colonel Sheppard then leads a raid on Ladon's compound. However, though they stun all of Ladon's guards, they find that the ZPM has long run out of power, and they are gassed.

In the meantime, Dr. Beckett determines that the remains of the men found in the fire are not those of Major Lorne and his team while at the same time Teyla and Ronon discover a hit list for members of the Atlantis expedition.

Sheppard wakes to be confronted by Cowen, who planned Ladon's trap. He is soon thrown into prison, where he finds the rest of the raiding team, as well as the captured off-world team led by Major Lorne.

In Atlantis, the team receives Cowen's demands. They inform him that Dahlia and the others can be saved, with their technology, from death. Ladon, who was still planning a coup the whole time, frees Shepard and company, escapes through the Stargate, and detonates a nuclear bomb, killing Cowen and his elite guard.