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.

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.

Olivia's sister, Rachel, visits; Walter, Peter and Olivia try to solve the murder of an esteemed epidemiologist, which may be linked to Olivia's abduction.

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.

Setting the stage for the dramatic and revealing first season finale are a sudden and unexpected attack on someone with close ties to Fringe Division, the return of bioterrorist David Robert Jones and the inexplicable disappearance of Walter. Find out more about the mysterious events surrounding our trio when questions are answered, observations made, loyalties are tested and the elusive William Bell is finally introduced.

A highway construction worker is the seventh in a series of mysterious disappearances in Lansdale, PA. The team come to investigate and finds traces of a mysterious paralytic. Meanwhile, Walter tries to send frogs to an alternate reality and Olivia realizes her recent trip has altered her in ways she can barely understand.

The Observer chooses to do something other than observe, abducting a college student. However, when the Fringe team investigates, they discover that there is more than one Observer.. in both time and space.

Walter explains to Olivia how Peter came from the alternate universe, and how he was willing to risk everything to save his son.

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.

When Walter discovers that Peter has traveled to the alternate universe, he and Olivia gather three cortexiphan children with the ability to transition safely between the two Earths.

Walternate asks Peter to help complete the device, while the fugitives Walter and Olivia are reunited with William Bell. Meanwhile, the alternate world's Fringe Division closes in on the invaders, and Peter must make a life-shattering decision.

After the extraordinary turn of events that shockingly left an imprisoned Olivia "over there," she fights to find her way home. Meanwhile, Peter and Walter try to move on with their lives unknowingly alongside alternate Olivia.

Peter struggles to cope with recent events; Olivia searches for an ally; a device that communicates between universes is discovered...

An Observer makes contact with the Fringe Team to help rectify a mistake. Meanwhile, Walter befriends Roscoe Joyce, keyboardist for Walter's favorite 1970s band, "Violet Sedan Chair." Walter will learn the real reason the band broke up, and realize that the lives of these two men, who have never met before, overlap in strange and unexpected ways.

In a follow up to last season’s “Peter” flashback episode, the all-new “Six Months Later” episode revisits a poignant period of time for both the Bishops and Olivia.

When the Fringe team investigates an apparent suicide victim, they uncover a second set of fingerprints leading them to a woman with uncanny characteristics that cannot die.

In an effort to remove Bell's consciousness from Olivia's mind, Peter, Bell, and Walter enter Olivia's subconscious and attempt to find her personality, which has hidden itself somewhere safe.

As the thrilling third season propels to a climactic close, questions will be answered as Peter confronts his destiny and a beloved team member meets an untimely demise.

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.

Olivia uncovers a dangerous force that may be connected to past experiments with Cortexiphan. The investigation forces Walter to leave the lab for the first time in years and travel to Massive Dynamic to examine old case files. Walter struggles with his emotional state as he confronts the demons of his past.

Over Here Astrid gets an unexpected visit from her Alternate, while Peter and Olivia track a killer using a toxin that has yet to be invented. Both universes collide in a case that pushes the boundaries of what is possible.

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

The Fringe team goes back to the future as the story jumps ahead to 2036, when the Observers and the Fringe team engage in a game-changing battle.

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 is pushed to the breaking point as they desperately attempt to prevent a catastrophic event that threatens the lives of everyone.