Walter thinks the abduction of a young music prodigy is linked back to his old bunkmate at St. Claire's Hospital. When he kidnaps the child he sees a sequence of flashing lights. Olivia wants Walter to return to the mental institution much to Peter's outcry, but Walter's determination to help ends up having chilling ramifications.

The team is called in to investigate why a man jumps out a window because he thinks he's being attacked by butterflies. Olivia gets some breaks in solving the case from her former partner and that she is so desperate to rid herself of him that she demands to go back into the tank. Meanwhile, some former friends and current foes of Peter find out that he's back in Boston.

The team is called in on a bank robbery similar to other robberies in the area but this particular bank has the thief embedded inside the steel wall of the bank. Somehow the thieves have found a way to defy the law of physics. Walter thinks they're after something of his. As the investigation deepens it all comes to a head when the thieves ambush one of the team.

When the Fringe Division delves into another bizarre occurrence aboard an international jumbo jet, freakish remains are discovered at the crash site. Memories tip the team toward some promising leads, but the bigger picture and mysterious threat eludes them. With limited options and insufficient intelligence, Olivia and Peter go undercover.

German agents question Olivia about her "relationship" with David Robert Jones, an escaped prisoner questioned months earlier now living in the U.S. The Fringe Division investigates a threatening case where victims die faceless from their orifices suddenly sealing.