After the radical faction of the Fifth Column murders three Peace Ambassadors, Erica goes on a mission to hunt down their leader, Eli Cohn, a former Mossad agent. Meanwhile, as Jack and other priests around the globe begin to speak out against the Visitors, Anna heads to the Vatican in an effort to convince the leaders of organized religion that the Visitors truly are "of peace".

Anna uses her newest gift to mankind, "Concordia," as a cover to hide an invading fleet of breeding vessels that will be used to ensure the perpetuation of Visitors for future generations. Meanwhile, Eli Cohn (guest star Oded Fehr) tries to convince Erica and the Fifth Column that the "Concordia" gala is the perfect time to assassinate Anna.

Anna, enraged at the increasing audacity of the Fifth Column attacks, enlists Ryan in an attempt to wipe out the Fifth Column in one fell swoop. Meanwhile, Father Travis, following Vatican orders, asks Jack to leave the church, and Lisa meets Diana, her grandmother – who Anna said was dead – for the first time.