level of 190,[1] and fluency in English, Arabic, Persian, Latin, Greek, Cantonese, Russian, and Spanish, Peter became a college drop-out with gambling debts, a jack-of-all-trades, and a master con artist.

")[1][5] Additionally, Peter has trouble with the mafia because he owes an undisclosed amount of money to "Big Eddie," a crime lord who had been hunting him for some time.

Peter was first seen setting up a business deal in Baghdad, Iraq, when he was blackmailed by Olivia Dunham to gain access to his father.

Following this incident, Peter realizes that "The Pattern" does actually exist, and vows to remain in Boston until he discovers the truth, becoming a civilian consultant for U.S. Department of Homeland Security, in the area of fringe science.

Olivia does not remember saying this, or her experience on the Other Side, but this phrase deeply affects Peter, who explains that his mother used to say it to him every night before he went to bed.

[11] By episode 2x04, "Momentum Deferred," Olivia remembers meeting Bell in the other dimension, and learning of an impending war between both universes, and that an army of "shape-shifters" from the other side is working undercover in the prime-universe.

[13] In the episode "Jacksonville", Walter reactivates Olivia's Cortexiphan abilities, allowing her to identify objects from the Other Side because of a distinctive "glimmer" they display.

At the end of the episode, Olivia notifies Walter that Peter has checked out of the hospital and is on the run to resume his isolated and nomadic pre-Fringe life.

With Peter subdued, Newton calls out to "Mr. Secretary" (the man he pulled over from the Other Side), who is revealed to be his biological father, Walter (Walternate), from the other universe.

[16] Peter agrees to accompany his biological father to his home universe, which is captured on security cameras and sent to Olivia and Walter, who are devastated by the loss.

[20] "Fauxlivia" returns to her home universe and finds herself six weeks pregnant, Walternate welcomes the news and offers his full support, though it seems he has an ulterior plans for the pregnancy and baby.

In the ensuing chase between them, Peter corners September on a rooftop and asks what will happen to him, if the "doomsday machine" will in fact destroy both him and this universe.

At the end of the episode, September and another Observer, December, watch the Bishop house, and reveal the reason why they orchestrated the day's events—to see if Walter is finally able to let Peter die, which he apparently is.

Peter and the science team discovered that our side had another weapon, with the pieces scattered all over the world, which was originally constructed by "The First People," the first human species on Earth.

Through quantum entanglement, the weapon on this side is also activated, and, according to Sam Weiss, becomes "frustrated," after Peter attempts to enter it in an effort to prevent the destruction of this universe.

Whilst inside the machine, Peter's consciousness is propelled 15 years through time, arriving in 2026, outside the completed One World Trade Center.

In "The Day We Died," the season three finale set in 2026, Peter, 47 years old and a leading member of a more militarized Fringe Division, is married to Olivia, who has taken Broyles' place as commanding officer.

After the Peter from 2011 experiences life in 2026, he returns to 2011, and uses the machine to create a "bridge" between both worlds, where both Walters, and both Olivias, can hopefully forget their differences to save the multiverse.

Just as happened in the original timeline, Walter was locked away in St. Claire's Mental Hospital for seventeen years, until Olivia Dunham had him released in order to help her partner and lover John Scott.

Also, other events which Peter only had a slight hand in are erased entirely, such as the prime-universe version of Lincoln Lee's first meeting with the Fringe Division.

Olivia lives with the constant feeling that something is missing from her life, and joined Fringe Division because she believed it would help her find answers.

She also managed to kill her stepfather (whereas in the original timeline she only wounded him), and was adopted by Nina Sharp, who continues to be a maternal figure in her life.

Without Peter's presence, Walter has even less of a grip of reality, becoming agoraphobic, afraid to leave the lab, hypersensitive to germs that may or may not be there, and prone to destructive "episodes."

Once the device is constructed however, September decides not to activate it, and Walter sees a reflection of Peter in the screen of his television, causing him to panic.

He resurfaces (quite literally) in Reiden Lake, and is taken to the hospital, where, much to the confusion of the Fringe Division, he asks for Olivia and Walter, and reveals knowledge that no citizen should know.

Olivia and Lincoln desire his help to gather intelligence on the alternate universe, especially regarding a new and dangerous form of human-shapeshifters, which they believe are under the direction of Walternate.

After crossing over, Lincoln and Peter make a failed attempt to gain access to Walternate and are captured by the alternate Fringe Division.

However, en route to being interrogated, their driver receives a mysterious call and kills his fellow officer and attempts to frame them for the crime and execute them.

When he is first introduced, Peter is callous and cold to Olivia, showing little concern for Agent Scott, but he grows to become more sympathetic as details of his unhappy and often traumatic childhood are revealed.

In the prime timeline, Peter was in love with Olivia, but was unaware that he fathered a child with Fauxlivia, whom she named Henry, in the alternate universe.