After a plane from Hamburg returns with no survivors, FBI agent Olivia Dunham goes after the only person that might shed some light on the incident - a scientist that has been in a mental hospital for the last 17 years.

A woman gives birth to a baby who ages eighty years in just a few minutes. Olivia soon finds connection between the incident and a serial killer she had been chasing.

Following a strange apparent terrorist attack on a bus, Olivia, Peter and Walter find a man who foresees future disasters before they happen.

A strange cylinder which is somehow connected to Walter and a man known as "the Observer" appears from the ground at a construction site.

An elevator crashes, killing a number of people, leading Olivia and the Bishops to a man who appears to unknowingly be able to manipulate electricity.

A number of people in a diner die of radiation exposure and Olivia and the Bishops believe a woman who disappeared two weeks earlier was the source.

An FBI agent experiencing huge pain is brought to a hospital where it is discovered that there is a strange parasite wrapped around his heart.

A young musical genius is kidnapped and Walter recalls a patient at St Clair's who might have been kidnapped by the same people and forced to try and figure out the solution to an equation.

The Fringe division investigate the questionable fall of a Massive Dynamic executive analyst. John helps Olivia crack the case. Peter meets up with an old girlfriend.

After a series of mysterious bank robberies, a suspect is found embedded into a wall, causing Walter to realize that they have not only found a way to literally walk through walls, but are looking for something he's made in the past.

Olivia has been abducted, and Broyles and the Fringe division must investigate her disappearance - while also undergoing an audit by an agent from Olivia's past who bears a major grudge against her.

Two men's brains are liquefied and their only apparent connection is that they both downloaded a huge file before dying.

A man undergoes a painful and ultimately fatal transformation aboard a plane. Meanwhile, Nina Sharp and Broyles reveal more information about John Scott to Olivia.

The team investigates a number of people who died faceless after their orifices are sealed while German agents investigating David Robert Jones' escape question Olivia.

A mysterious child is recovered from a secret chamber that has been sealed for more than a half-century.

A group of animal rights activists are killed in action when trying to flee from a lab animal which doesn't exist in nature.

FBI agent Dunham believes that she is killing random people in her dreams.

Walter examines a number of dead bodies that had the spinal fluid removed. Olivia and Charlie go after the scientist who created the person behind the murders.

The Fringe team investigate a case of spontaneous human combustion. Olivia starts experiencing visions of the alternate Universe. She uses this ability to solve the case.

David Robert Jones comes out of hiding following an attempt on Nina Sharp's life while Walter leaves accompanied by the mysterious Observer.

Olivia is in a car accident, an unusual person is looking for a member of the team, and Walter makes plans for celebrating Peter's birthday.

Olivia and Peter investigate a series of strange disappearances. Olivia hears and sees things from the alternate Universe but fails to realize Charlie isn't really Charlie.

The Fringe division investigates the explosion of a police officer. Olivia starts having visions about her experience on the other side.

Walter analyzes the body of a shapeshifter and then reconnects with an old patient that has the ability to distinguish the people from the other world. Olivia finally recalls her encounter with Belly.

People who once had sleeping problems but were cured by having a biochip inserted in their brain suddenly start to die. Walter suspects the chips were accessed by someone who used mind control.

A teenager comes back from the dead possessed by a soldier who's gone missing. Walter does an experiment so that the Fringe team can find the soldier's murderer.

Walter and Olivia travel to the parallel universe, and the anticipated face-off between Walter Bishop and William Bell occurs.

Sacrifices will be made and both universes may never be the same again after Walter and Olivia visit the "other side."

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.

In the alternate universe, Olivia and the Fringe Division investigate weird accidents with casualties apparently with no connection except ballpoint pens found on the spots. But when Olivia sees the freak Milo, she suspects that he might be the responsible. Olivia and Charlie investigates and soon they follow a lead to a hospital where they learn what happened to Milo.

In the parallel universe, a man releases his twin brother from an area in quarantine, removing him from the amber. The Fringe Division investigates the case that is classified since The Secretary does not want that the population learns that the family and friends are alive enclosed in amber. Olivia interviews Matthew, who is the twin brother of Joshua, and suspects that he is lying. Meanwhile The Secretary lures Olivia and convinces her to be submitted to n experiment while she has daydreams with Peter.

In the parallel universe, a kidnapper called The Candy Man abducts the boy Max. The Fringe Division is assigned to investigate the case and soon Olivia learns that Broyles' son Christopher was also abducted two years ago and returned blind and with physical deficiencies to his family. She asks Broyles to interview Christopher to see any missing information but Broyles does not accept; however his wife agrees that Olivia meets Christopher. Olivia recalls an old case and guess whether The Candy Man would be draining the pituitary gland from the children to use the hormones to stay young. Based on the received information, Olivia and Broyles meet Reverend Marcus, who was a former physician and now is responsible for a church where they believe the abductor is a member. Meanwhile Olivia meets Henry and asks him to help her to go to the Liberty Island to use the deprivation tank to return to her universe.

In the parallel universe, the Fringe Division investigates a case where a man was eaten from inside out by an extinct beetle. Meanwhile Broyles is considered missing and Lincoln is the head of the division. Olivia welcomes her boyfriend Frank that has just returned from Texas and wants to propose her. When a second man is also eaten by the insects, the Fringe Division identifies the scientist Dr. Armand Silva that was researching the cure for avian flu using this insect. Lincoln and Olivia goes to his address and split. Lincoln is locked in a refrigerating chamber while Olivia is brought to his laboratory, where she drinks water. Dr. Silva explains that only human beings are capable to host the beetle and a new cycle has just began. Olivia concludes that she has been infected by the insect and despairs.

The intensity of life "over there" accelerates as Olivia finds herself in mortal danger.

In the parallel universe, the Fringe Division investigates a case where a man was eaten from inside out by an extinct beetle. Meanwhile Broyles is considered missing and Lincoln is the head of the division. Olivia welcomes her boyfriend Frank that has just returned from Texas and wants to propose her. When a second man is also eaten by the insects, the Fringe Division identifies the scientist Dr. Armand Silva that was researching the cure for avian flu using this insect. Lincoln and Olivia goes to his address and split. Lincoln is locked in a refrigerating chamber while Olivia is brought to his laboratory, where she drinks water. Dr. Silva explains that only human beings are capable to host the beetle and a new cycle has just began. Olivia concludes that she has been infected by the insect and despairs.

Olivia is in a car accident, an unusual person is looking for a member of the team, and Walter makes plans for celebrating Peter's birthday.

A group of animal rights activists are killed in action when trying to flee from a lab animal which doesn't exist in nature.

A teenager comes back from the dead possessed by a soldier who's gone missing. Walter does an experiment so that the Fringe team can find the soldier's murderer.

In the alternate universe, Olivia and the Fringe Division investigate weird accidents with casualties apparently with no connection except ballpoint pens found on the spots. But when Olivia sees the freak Milo, she suspects that he might be the responsible. Olivia and Charlie investigates and soon they follow a lead to a hospital where they learn what happened to Milo.

Walter analyzes the body of a shapeshifter and then reconnects with an old patient that has the ability to distinguish the people from the other world. Olivia finally recalls her encounter with Belly.

Walter and Olivia travel to the parallel universe, and the anticipated face-off between Walter Bishop and William Bell occurs.

An elevator crashes, killing a number of people, leading Olivia and the Bishops to a man who appears to unknowingly be able to manipulate electricity.

People who once had sleeping problems but were cured by having a biochip inserted in their brain suddenly start to die. Walter suspects the chips were accessed by someone who used mind control.

Olivia and Peter investigate a series of strange disappearances. Olivia hears and sees things from the alternate Universe but fails to realize Charlie isn't really Charlie.