This season episodes open with an orange title sequence indicating that the timelines have changed and that the episode can take place in either universe.

This week’s episode of ‘Fringe’ asks an intriguing question—can one event change the course of a life? The writers have taken advantage of having access to both universes, courtesy of the Bridge Area, to explore this issue. In our universe John is a forensic psychologist, but on the other side, John is a serial killer. Are they different because of environment, a series of events, or something else?

Fauxlivia and the rest of the altverse Fringe Division have been looking for John for about five years. He killed twenty-two people; they didn’t catch a break until his twenty-third victim when he left a stray hair. His method of murder is unique. John drills a hole in the back of his victim’s skull, inserts a tube into the brain, and chemicals lower the brain’s temperature, freezing the victim from the inside out. During this process, John is connected to the victim; he has an implant in his brain so he can plug himself into his device. John questions his victims about their happiest memories and experiences their happy moments as they die. To help catch John, Fauxlivia asks Olivia to bring our John to the alternate universe. Since she learned a lot about Olivia by living in her apartment, Fauxlivia thinks the other John will be able to find clues in the killer’s house and lead her to the killer.

Olivia and Broyles meet Fauxlivia in the Bridge Area. After debating the details with Broyles, Olivia agrees to help. This John will be tranquilized and not told where he is going. Olivia will accompany him, but the rules of the truce will be in effect. Olivia is in charge over here while Fauxlivia and her Fringe Division is in charge on the other side. In the alternate universe, our John is taken to the killer’s home. Fauxlivia dresses like Olivia to maintain the illusion. Our John profiles the suspect: he’s intelligent, needs to be in control, is fascinated with the brain, and felt deprived during childhood. Fauxlivia’s plan backfires; John recognizes items from his own past and discovers a picture of his father. Frightened and confused, John rushes outside. Olivia, who had been listening in a car with alt-Lee, goes to him. John sees both Olivias and has to be told the truth.

Fauxlivia has John investigate his double's house.

Olivia questions John. John admits that what is in the killer John is in him as well. Since he was young, there has been darkness inside of him. His father saw it and used brutality to try to fix him. John wanted to act on his urges, but never did because he met a woman named Marjorie. He has always wanted to know what his life would have been like if he had never met her. Being in the altverse has shown him what he could’ve become. According to him, one event, one person, is what possibly allowed him to lead a regular life, but he would like to meet this other self to be sure. Also, John wants to tell his other self that there is a way to control the urges, but Olivia says that the alt-John’s course is set. John excuses himself to go to the bathroom, but he slips away. Olivia works with the Fringe Division to find him.

Killer John has selected his latest victim, a happy mother named Noreen. He is in the process of hooking her up to his machine when our John finds him. The killer is shocked to see his doppelgänger, but our John explains that they had the same life but that there is an event that separated their paths. By comparing stories, they realize that one night in October is when their paths diverged. When they were ten, they went to the fair. Their father found the dead things. The alt-John hid but was found by his father who beat him for three days. Our John ran and ended up in a field where he met a woman, Marjorie, who taught him how to fight the urges and the darkness and enter the light. John realizes that meeting Marjorie was the key to making him the man he is and wants to teach alt-John what she taught him. They argue. Alt-John attacks John and attaches him to his machine.

Olivia and alt-Lee find John and Noreen alive. Alt-John has the memories of Marjorie; for the first time, he feels and realizes what he has done. Distraught and overcome with emotions, he shoots himself. Back in our universe, John cannot remember going to the other side or Marjorie. Olivia is concerned, and Broyles says that John will have to be watched because Marjorie was the only thing keeping him from becoming a killer. Olivia questions John. Although he doesn’t remember Marjorie, he remembers what she taught him—no matter how deep in the darkness you are, you can still find your way to the light. Broyles comments that he thinks there are people and moments that leave indelible impressions on one’s soul so powerful that one can never forget the message.

This episode also picks up the thread of one person impacting events by revealing more about the Peter-less universes. In the altverse, Fauxlivia is still with Frank, meaning there was no Peter for her to fall in love with, and alt-Broyles is still alive, so either he didn’t get caught helping Olivia or she got home another way. On this side, Walter is heavily medicated, and he is less focused and more befuddled than ever. He lacks confidence and does not trust himself. The Walter who had Peter in his life would be investigating why he is seeing a strange man in the mirror. This Walter covers all reflective surfaces because he believes he is crazy. He is also playing loud music. Why? Because he has started to hear Peter’s voice. The show ends with Walter hearing Peter. Peter says, “I’m here Walter. Please help me.”

What fascinated me about this episode is how the writers went back to Walter’s explanation of how different timelines form. Walter told Olivia and Peter that different actions and decisions can trigger new timelines and new universes. Obviously big moments can cause new timelines to form, and the writers could have easily created an episode about a momentous occasion like war or a presidential election, but the writers of Fringe don’t do easy.

Perhaps some viewers reacted like I did at first. One moment can change the course of a life? Really? But then I thought about my own life. Is there a moment when a decision was made that drastically impacted my life? Yes, and it happened before I was born. My maternal grandmother was given a choice: either agree to allow my mother to live with her or force my mother to marry my father. In this universe, my parents married, and I grew up with a man who would never win any “Father of the Year” awards. By making me realize that there could be an alt-Michelle in another universe with a drastically different life than mine, the writers show how one man, Peter, can radically alter the fates of others in not one but two universes. By crafting a personal story instead of an over-the-top extravaganza, the writers rooted the show in emotional reality, proving that good science fiction can be, and should be, more than cool gadgets and special effects.