Complete story — includes the ending
In an alternate reality, Detective John Sheppard and FBI Agent Richard Woolsey find themselves in the midst of a CSI -like murder case involving several killings apparently of Wraith origin in Las Vegas, Nevada. It's eventually revealed that this Wraith is the only survivor of a hive ship that attacked Earth and was destroyed. The Wraith plans to send a transmission to the other Wraith to lead them to Earth, but Sheppard finds him and enters a gunfight that leaves Sheppard mortally wounded. As the Wraith is about to kill him, two A-10 Thunderbolt IIs sent by Woolsey - whom Sheppard alerted earlier through Dr. Rod McKay - arrive. The Wraith quickly activates his transmitter before the fighters destroy it and him. The transmission never reaches Pegasus, thus saving the alternate Earth, but is sent through to other realities where it will reach Pegasus.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Stargate Atlantis season 5. HTML formatting and reference markers removed. · Content license