A Cylon, who calls himself Leoben, is discovered on one of the ships in the fleet. Commander Adama sends Kara to interrogate him - or, rather, it. The Cylon tells Kara that he planted a nuclear device on one of the ships. Although she doesn't believe it, Kara passes on the warning.
As her colleagues search for the device, Kara engages Leoben in a battle of wills. Theological debates about souls and the humanity of Cylons lead to mind games, threats, and, ultimately, torture. Taking a personal interest in what Leoben has to say, President Roslin joins the interrogation.
On Galactica, Sharon asks Baltar to try out his new Cylon-detecting technology on her.
Meanwhile, on far-off Caprica, another Sharon conspires with her Cylon associates Doral and Number Six to convince Helo to remain on the planet and start a new life.