Stargate Atlantis: The Chosen (Stargate Atlantis)

The Stargate Atlantis team encounter a society where high priests of the local cult are able to protect the society from attacks by the Wraith by using technology left behind by the Ancients. However, the genetic ability to use the weapons has faded over successive generations, leaving the people increasingly vulnerable to attack. With the Wraith growing ever bolder in their attacks, the team must decide whether to inoculate the priests with a gene therapy which will restore their abilities, and also decide whether or not to withhold the therapy from the rest of the population in order to shore up the dominance of the high priests.