As Sheppard’s team searches for unused gates to build an easier and faster path back to the Milky Way, they happen on a simple agrarian culture on a planet with an unused orbital gate. There the find Lucius, a town folk who seems to be extremely loved by all those around him. When Dr. Beckett later brings Lucius back to Atlantis unannounced, things there become strange too. Lucius seems to be able to control everyone in Atlantis, except for Col. Sheppard, who has had a recent cold.

Sheppard must find a way to overcome Lucius’ control over the crew, before he becomes a target for opposing their new guest.