Stargate Atlantis S05 E06 The Shrine

"A new gate will open. A lost city will rise again."

Dr. Rodney McKay is infected with the Pegasus equivalent of Alzheimer's disease, known as Second Childhood, a common illness among the elderly in the galaxy. The only way to save him is a shrine on Talus. The downside is that it has turned into a Wraith outpost.