Season 2 Episode 20 (Aired: April 29 th, 2010 on FOX)
Peter figured out he's been abducted from the other side and took off. Walter smokes weed to cope. Olivia drops off her niece at the lab. Ella asks for a story and Walter invents one centered around a stolen heart with all our main characters assigned major parts, blending fifty's film noir trope with cell phones, their current line of investigation, and musical elements.
Walter Bishop (John Noble) compensates Peter's (Joshua Jackson) rejection of him after finding out he's been taken from the other universe by smoking a blend of weed he calls "Brown Betty" and labeling the odds and ends in the lab to bring order to his life. In comes Olivia (Anna Torv) with her niece Ella (Lilly Pilyblad) whom she babysits while her sister Rachel (Ari Graynor) is in Chicago. She would like to follow a lead in Peter's disappearance and asks Astrid (Jasika Nicole) to look after Ella. Since Walter is no good at playing games Ella asks for a story. The task of storyteller had fallen to Peter's mother, Walter apologizes. He was to busy then and doesn't know any stories. Didn't his own parents tell him any, Ella insists, which sets off memories of his mother not only loving detective stories but also musicals.
So, once upon a time, there was an accomplished private detective named Olivia who gave up on her profession because there was one mystery she couldn't solve: how to mend a broken heart. In the middle of her packing up her office a woman comes in to beg her to take her case. Her boyfriend Peter has gone missing and she fears the worst. Disillusioned Olivia tells her that by the time she finds the missing boyfriends usually her clients wished they were, in fact, dead. One must know, Walter says, that she once had believed in great love. Rachel is absolutely convinced that Peter is not that kind of guy and Olivia, if for no other reason than to see if great love really exist, finally accepts the case.
Her first lead is a sketch of a logo that a contact at the police identifies as the one used by Massive Dynamic. A company that would make money at all cost, never missing an opportunity to rip off the little guy and making profits off the ingenuity of others. There she meets Nina Sharp (Blair Brown) who tells her Peter is a con-man dabbling in anything from small scam to large scale industrial espionage. She leaves with a warning that Peter is a very dangerous man.
Rachel is killed. Turns out she was an actress and her name not Rachel - an adjustment Walter makes on Ella's insistence that he tells the story wrong because people who are really in love don't die. A notebook Olivia takes from the scene leads her to brilliant scientist Walter Bishop. The scientist who invented all the things that bring joy to the world like teddy bears, bubblegum, rainbows, hugs, and singing corpses had a bad heart, but it got replaced. But someone took the glass heart from him while he was sleeping and since Olivia is well known for her expertise in matters of the heart he hired an actress to get her to look for his lab assistant Peter who stole it. For the moment he manages to keep himself going, but time is getting short.
Soon Olivia is attacked with a laser scalpel that again leads her back to Massive Dynamic. Sharp denies the company's involvement and points Olivia in the direction of a group of men that call themselves Watchers. If they tell her to stay away from Peter she better listen. Olivia drives up to Nina's house at night and happens to overhear her talking to William Bell (Leonard Nimoy). Next thing she knows she awakens on a ship and Nina Sharp and a Watcher stuff her into a wooden coffin for disposal at sea. It floats long enough for Peter to rescue her. He knew she was looking for him and had followed her.
At his hideout Peter shows Olivia a map with 147 pins, each representing a child hurt by Walter Bishop. Walter invented many wondrous and wonderful things, Peter agrees, but he stole the ideas for them from the dreams of children and replaced them with nightmares. Olivia learns that the glass heart really is Peter's, that he was born with the condition, and, not knowing what Walter was capable of for the longest time, had even be willing to die for him, giving his heart to the man who's life he thought so much more valuable than his for bringing joy to the world.
Just when Peter finishes his tale his place is ambushed by Watchers. Peter's heart is taken but Olivia manages to stabilize him with batteries she finds in a kitchen drawer. Together they confront Walter and take Peter's heart back, leaving the scientist to wither away, because some things cannot be forgiven.
Ella is not happy with the ending since all stories that start with "once upon a time" have to end with "happily ever after" and so she makes up one more to her liking. In it Walter gets a second chance to set things right. Peter forgives him and breaks his heart in two, sharing one half with Walter. Because his special heart is so magical, it works out for them. Together they make more goodness and lived happily ever after.
When Olivia returns Ella tells her uncle Walter isn't very good at telling stories because it was all sad, but, she beams, she fixed the ending for him. In real life Olivia didn't find a trace of Peter and the episode ends with an Observer expressing concern over the developments.
The episode was heralded as Fringe's foray into the world of musicals in the way of Buffy's famous "Once More With Feeling," which set the standard for all to follow. Did it measure up? No, but then in my opinion it didn't have to, touchingly offering a glimpse into Walter's mind and heart instead. On Buffy during the course of bright song and dance the characters revealed awful truths to each other. In Fringe we and the characters knew all along and no character dynamics were changed at the end, nor the the overall story arc pushed forward. "Brown Betty" was a fun ride and there was far less singing going on than anyone might have feared.