Erica finds her life in danger when she's attacked at home. A dangerous new member is recruited for the Resistance as the Visitors shore up their defenses. Anna wonders why Chad hasn't followed up on his diagnosed aneurysm and Ryan's concern grows over Val's "abnormal" pregnancy.

Anna introduces her pilot program to invite select groups of humans to stay on each of the 29 space ships. Ryan must deal with the fact that Valerie's pregnancy is wildly accelerated. Tyler learns a secret about his mom and one of the team makes a sacrifice to save Ryan.

Erica, Ryan and Jack go on a harrowing mission to find the legendary John May in order to rescue Georgie. Anna brings Chad aboard the Mothership for a story on her Live Aboard Program and Tyler confronts his mom about his mysterious past.

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.