. The show was a spin off of sister show, Stargate SG-1. Stargate Atlantis re-introduced supporting characters from the SG-1 universe, such as Elizabeth Weir and Rodney McKay among others. The show also included new characters such as Teyla Emmagan and John Sheppard. The first season is about a military-science expedition team discovering Atlantis and exploring the Pegasus Galaxy. However, there is no way to return home, and they inadvertently wake a hostile alien race known as the Wraith, whose primary goal is to gather a fleet to invade Atlantis and find their new "feeding ground", Earth.