Season Four
Neither Here Nor There
Episode #: 401
Air Date: 09.23.11
The fourth season begins one week after Peter vanished, and as the two universes maintain an uneasy alliance, Lincoln Lee helps the Fringe team on a shape-shifting investigation that hits close to home. (TV Guide)
One Night in October
Episode #: 402
Air Date: 09.30.11
The Fringe teams work together when a serial killer "over there" builds an impressive body count, but the case takes an interesting turn after the murderer's alternate identity "over here," a forensic psychologist, is brought into the investigation, which opens up the possibility of transporting civilians from one universe to the other. (TV Guide)
Alone In the World
Episode #: 403
Air Date: 10.07.11
Two 12-year-old bullies are found dead after tormenting another boy, but the abnormally rapid decomposition of their bodies leads to the Fringe team's discovery of a strange entity and a trail of more victims. Meanwhile, Walter's hallucinations are beginning to take their toll. (TV Guide)
Subject 9
Episode #: 404
Air Date: 10.14.11
Walter is wary of leaving the sanctuary of his lab for the first time in years when he and Olivia go to Massive Dynamic in New York to study old files after she discovers a powerful force that may be linked to his Cortexiphan experiments. (TV Guide)
Novation
Episode #: 405
Air Date: 11.04.11
The threatening return of the translucent shape-shifters coincides with the reemergence of a former Massive Dynamic scientist. Meanwhile, Walter gets a visit in the lab from Nina Sharp. (TV Guide)
And Those We've Left Behind
Episode #: 406
Air Date: 11.11.11
An electrical engineer (Stephen Root) and his wife, a theoretical physicist, pitch in during a frantic search for a pattern between time-loop anomalies. (TV Guide)
Wallflower
Episode #: 407
Air Date: 11.18.11
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. (FOX)
Back to Where You've Never Been
Episode #: 408
Air Date: 01.13.12
Olivia and Lincoln take drastic measures to deal with the looming threat from the translucent shapeshifters, while helping Peter find his way home. Something "over there" occurs that hasn't happened since the universes were linked. (FOX)
Enemy of My Enemy
Episode #: 409
Air Date: 01.20.12
The alternate Fringe division confronts a powerful new adversary during Peter's visit to the other side. (TV Guide)
Forced Perspective
Episode #: 410
Air Date: 01.27.12
Olivia is preoccupied by a warning from the Observers, while Peter helps with the search for a girl with mysterious powers to see the future. (TV Guide)
Making Angels
Episode #: 411
Air Date: 02.03.12
Astrid gets a surprise visit from her counterpart in the alternate universe; Peter and Olivia are on the trail of a killer equipped with a toxic weapon that defies chronological description. (TV Guide)
Welcome to Westfield
Episode #: 412
Air Date: 02.10.12
Peter, Olivia and Walter are trapped in a town from which there is no escape during a mysterious Fringe event. (TV Guide)
A Better Human Being
Episode #: 413
Air Date: 02.17.12
A patient with a mental disorder seems to be linked to a series of murders, but the ensuing investigation helps Olivia discover even more surprises. (TV Guide)
The End of All Things
Episode #: 414
Air Date: 02.24.12
A series of life-threatening events call for extraordinary measures by Peter and the rest of the Fringe team. (TV Guide)
A Short Story About Love
Episode #: 415
Air Date: 03.23.12
A killer targeting love is investigated by the Fringe team as Peter tries to decide what to do about Olivia. (TV Guide)
Nothing As It Seems
Episode #: 416
Air Date: 03.30.12
A case is familiar to Peter but brand-new to the rest of the team. (TV Guide)
Everything In Its Right Place
Episode #: 417
Air Date: 04.06.12
Lincoln goes to the alternate universe to help Fauxlivia and his own doppelganger hunt for a vigilante who may be linked to the shape-shifters. (TV Guide)
The Consultant
Episode #: 418
Air Date: 04.13.12
Walter goes to the alternate universe to help with the probe of a Fringe event that affects both worlds. Meanwhile, David Robert Jones makes his next target known. (TV Guide)
Letters of Transit
Episode #: 419
Air Date: 04.20.12
A jump ahead to the year 2036 finds the Fringe team and the Observers as participants in an epic battle. (TV Guide)
Worlds Apart
Episode #: 420
Air Date: 04.27.12
The Fringe teams from both worlds are united by a common cause; new developments are linked to the children from the Cortexiphan experiments. (TV Guide)
Brave New World, Part 1
Episode #: 421
Air Date: 05.04.12
Walter reluctantly revisits his painful past after terrifying cases of spontaneous human combustion. Meanwhile, the future of both universes is at stake when the Fringe team faces David Robert Jones in the mother of all battles. (TV Guide)
Brave New World, Part 2
Episode #: 422
Air Date: 05.11.12
The Fringe team is desperate to prevent a catastrophic event that could cause mass death and destruction. (TV Guide)