The team investigates a bus full of dead commuters that appear to be fossilized and uncover a man who has visions of pattern-related disturbances before they happen; Dr. Bishop requests a piano in the lab to help him process data.

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.

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.

As animal rights activists ransack a laboratory, they get more than they bargained for when one of the caged "animals" unleashes a ferocious appetite. Leaving grotesquely mutilated dead bodies in its wake, the scientifically engineered beast with the body of a lion, claws of an eagle, fangs of a viper, skin of a rhinoceros and tail of a serpent attacks Charlie. With Charlie’s life on the line, Walter must come face-to-face with both his past and the beast.

Olivia experiences "awake dreams," seeing elaborate visions of things not really there. While investigating a disturbing case of a woman who apparently spontaneously combusted, Olivia throws caution to the wind and explores her unexplained visions further. Meanwhile, Walter discusses key information about the Z.F.T. manifesto, and Peter reveals a secret that yields unexpected results in the case.

Olivia and the others of Fringe division attempt to determine the origin of Peter Bishop, who purports himself as Walter's son who had died as a young boy in the original time line.

Peter, Olivia and Walter come face to face with a mysterious and terrifying Fringe event as they get trapped in a town that there’s no escaping from.

Lincoln travels to the other side to join forces with Fauxlivia and his own alternate, as they search for a vigilante with a surprising connection to the shapeshifters.