A run-in with a Wraith Dart leaves the consciousness of a precocious Atlantis security officer trapped in Dr. McKay's mind.

The team tries to relax during a mandatory day off, until an explosion leaves three people dead -- and reveals that one scientist is a walking time bomb.

When a virus causes amnesia in everyone except Teyla and Ronon, the Atlantis team must work together to find a cure before their memories fade entirely.

An automated lockdown traps Atlantis personnel in various parts of the city, each of them hoping the others will come to their rescue.