The alternate universe Fringe Division investigates a shocking breach of security when a twin frees his brother from a quarantined Amber area. As the team sets out to crack this sophisticated case, Walternate experiments over there more with Olivia as she reenters the tank. Meanwhile, visions of Peter continue to haunt Olivia about returning to the “other side”.

Peter's visit to the other side intensifies as the alternate FRINGE division faces off against a formidable new foe in a harrowing race against time.