The Shrine - Plot

Plot

Jeannie Miller, Rodney McKay's sister, comes to Atlantis when she learns her brother has been infected with a mysterious disease known as the "Second Childhood", the Pegasus equivalent of fast on-set Alzheimer's disease. The Expedition gives Jeannie a chance to say goodbye; Rodney has already regressed to a childlike state and all attempts at medical intervention have failed. Jennifer Keller explains that McKay became infected with the Second Childhood parasite at some point over the past two weeks, and that she misinterpreted the first symptoms when they appeared after a mission to M44-5YN. The subsequent deterioration of McKay's mind is shown through a series of flashbacks and self-made video recordings. Keller blames herself for not catching the disease sooner, but refuses to give up even as McKay has only a few days left to live. Ronon Dex proposes an alternative: a shrine on the planet Talus that grants those afflicted with the Second Childhood a single day of mental clarity, followed by a quick death. Jeannie overrules Keller's wishes and asks that McKay be brought to the planet. Despite the fact that the planet has become a Wraith stronghold, Richard Woolsey reluctantly approves the mission.

The team reaches the shrine in a puddle jumper, where McKay miraculously returns to normal. Keller determines that the shrine is emitting dangerous radiation that is causing the parasite to shrink so as to protect itself. As the parasite would rapidly and fatally re-expand were McKay to leave the shrine, and they cannot retrieve medical supplies from Atlantis due to the Wraith, Keller operates on him inside the shrine using improvised tools. Once she drills into McKay's skull, the parasite leaves to escape the radiation, and is destroyed by Ronon. At the end of the episode, Keller watches one of McKay's video diary entries, where McKay confesses his love for her, putting a smile on her face.