The Fringe team is pushed to the brink as they try to save every living person from the schemes of Jones' superior.
Walter is forced to relive his past while investigating a series of spontaneous human combustions, while David Robert Jones begins his end game.
The Fringe team on both sides fight a common cause and developments are made regarding the Cortexiphan children.
In the year 2036, a new Fringe team takes on the Observers in a war that will change everything. But to win, they must resurrect a legendary figure from their past, someone who holds the secret to defeating the Observers once and for all.
While David Robert Jones goes after his next target, Walter visits the Other Side to help the team's counterparts with an investigation into a Fringe case that touches on both worlds.
Lincoln teams up with the Other Side and together they investigate a vigilante with a connection to the shapeshifters.
The team investigates a case involving a bizarre mutation that Peter solved in his original timeline four years ago.
While Peter and Olivia deal with the emotional consequences of the Observer's revelations to Peter about his future, the Fringe team investigates the case of a killer who seems intent on murdering... love.
The dying Observer comes to see Walter and Peter, who must take extreme measures to learn what secrets he hides and determine if he knows where Olivia is. Meanwhile, David Robert Jones tries to force Olivia to use her cortexiphan abilities by torturing Nina.
While trying to cope with a new set of memories, Olivia discovers that a mentally ill patient who is a suspect in a string of murders may be connected to her own past. Meanwhile, Walter travels to the Other Side to discover the cause of Olivia's problems.
Olivia, Peter, and Walter visit the town of Westfield to investigate a report of Fringe activity, and discover that they are trapped.
While Peter and Olivia investigate murders involving an inexplicable toxin, Astrid and her Other Side counterpart meet for the first time.
While the Fringe team tracks down a girl who can predict the future, Olivia tries to cope with the message given to her by the Observers.
The Fringe Division of the Other Side must deal with both a visit from Peter and a new enemy, who is preparing a worlds-spanning operation to gain the mineral he needs to provide energy for his master plan.
While Olivia and Lincoln try to return Peter home, they try to cope with the looming threat of the transparent shapeshifters. Meanwhile, a traitor is revealed and an old enemy emerges from the shadows.
While Olivia copes with migraines, she and her team investigate an invisible force which kills its victims and causes the body to turn a ghostly white. As they trace the pattern of deaths, the Fringe team realizes that the force is linked to someone who died of an unknown genetic disorder.moreless
An electrical engineer and his wife, a professor of theoretical physics, are involved in a series of time loop anomalies.
The translucent shapeshifters return to plague Fringe division, and a former Massive Dynamic scientist is involved. Meanwhile, Walter meets with Nina Sharp.
Walter is forced to leave the lab for the first time in years when he and Olivia go to Massive Dynamic to examine files that may connect one of Walter's Cortexiphan test subjects to a new series of crimes.
As Walter tries to deal with his hallucinations, the Fringe team takes on a case of two 12-year-olds who died under mysterious circumstances after bullying another boy... and their bodies decompose at a remarkable rate of speed.
Bolivia and her team call upon their counterparts from This Side for help when a serial killer goes on a bloody rampage. They recruit the killer's This Side counterpart, a professor of forensic psychology, and try to transfer him to the Other Side without his knowledge to put together a profile on his other self. However, things soon go out of control when the professor realizes what's going on.moreless
The teams on the two worlds work together to solve the case of a shapeshifter, and Agent Lincoln Lee joins his world's team when no one remembers the existence of Peter Bishop.