Olivia, Walter and Peter are called in to investigate the death of a car salesman who was found in a pool of "goo," exactly like another man across the country. When Walter discovers that the "goo" is brain matter, the trio tries to figure out how the killer can liquefy human brains. As the deaths pile up, the investigation reveals a common thread linking the victims together in an unthinkable manner. Meanwhile, Olivia is horrified when the case places a loved one in harm's way

When Peter disappears, Walter seeks solace in marijuana. In that state of mind, he and Astrid babysit Olivia's niece Ella, and Walter tells her a fairy tale of a gentle inventor, a stolen glass heart, a detective looking for true love, and a mysterious group of bald men known as the Watchers.

A teenage girl pronounced brain dead wakes up in the middle of the operation to remove her organs... speaking numbers in Russian. When the Navy confirms that the numbers are nuclear launch codes and a missing officer named Rusk knows them, the search is on for the missing man.

The Fringe team faces a case that appears familiar to Peter. Strangely, it takes place in this timeline.

Olivia, along with Peter and Walter Bishop, investigates the strange death of a woman who had an even stranger child. The woman was pregnant for only hours, yet the baby she birthed was fully developed - and also aged eighty years in the span of a few minutes. Olivia asks Nina Sharp of Massive Dynamic for help.

As the Fringe team investigates a mentally ill patient who appears to be connected to a series of murders, frightening clues and connections are uncovered that lead Olivia to some shocking revelations.

The team investigate the case of a man who can project electricity... and is at the center of a series of strange deaths involving electricity.

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 continues to cope with the ominous warning from the Observers, while Peter and the team track a girl with the mysterious ability to predict death.

Following the recent shocking revelations and emotional events, Peter weighs his options as the Fringe team investigates a killer targeting love.

As the rogue Fringe team continues to fight off the oppressive Observers’ invasion, unforeseen events lead them into a forest where they encounter a strange subculture of people devoted to recording human history.

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.

Two young bullies are found dead and in just a few hours they rot to an advanced state of decomposition. The Fringe team investigates and uncovers an amorphous figure claiming more victims. Walter becomes increasingly distracted with his mental state.

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.

The team investigates a woman that re-appears after weeks of being missing with a rare disease. She also inexplicably causes pain and death to the people she meets. During the investigation, dangerous level of radiation are detected. Walter obsesses about cotton candy; Peter strikes a deal with Nina Sharp; and a truth about Olivia is discovered.

The Fringe Division is on the case when severely mutilated bodies drained of spinal cord fluid begin to pile up. After their investigation leads them to a scientist with possible ties to the Z.F.T. bioterrorist cell, they are shocked to discover the identity and motive of the killer. When the kills occur with increasing frequency, Olivia, Peter and Walter go to desperate lengths to stop them.

Walter is forced to revisit his painful past when a fringe event causes people to spontaneously combust; the team faces off with David Robert Jones.

The Fringe team revisits the Harvard lab, now under Observer control, to try to find the information they need as the team fights on in their mission to save the world.

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.

Broyles calls in the team to investigate a deadly explosion and its source: a strange cylinder unharmed despite the destruction. Olivia determines that the same cylinder, or a similar one, is responsible for similar events in widely diverse locations.

When a strange parasite attaches itself to the internal organs of a dying FBI agent, Olivia suspects a connection to the Pattern; Peter and Walter tap into a dead man's brain waves.

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.

Just one week after Peter Bishop saved the day and was then wiped from existence, the truce between the two worlds remains intact and the two sides are forced to work together. Lincoln Lee joins the Fringe team as they investigate a shapeshifter case that is very personal to him.

When a man mysteriously dies by an invisible force, his body rapidly begins turning ghostly white. The Fringe team learns that this is not an isolated incident, and there’s evidence that links the predator to someone who passed away with an unknown genetic disorder. Meanwhile, Olivia suffers from migraines.

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.