Fringe: Season 2, Episode 20

2 - 20: Brown Betty

Olivia sends her niece, Ella, to the lab for Walter and Astrid to look after while Olivia has to leave. To pass the time, Walter (who has just smoked his own special blend of marijuana called "Brown Betty") tells Ella a detective noir story, where Olivia, a private investigator, takes a case from her client (Rachel) to find her missing boyfriend (Peter) who is in possession of an artificial heart. Later, Olivia finds Rachel dead with her heart missing. This leads her to a scientist, Walter, who is creating inventions to benefit humanity, and believes Peter stole the artificial heart. While following Nina Sharp, Olivia is kidnapped, but saved by Peter. He reveals that the heart is his and that Walter is responsible for stealing dreams from children for his inventions and is replacing them with nightmares. After Peter's heart is then stolen during an Observer raid, they trace the attack back to Walter and confront him. In the original ending, Peter does not forgive Walter, but disappointed with it, Ella changes it to a happy one where Walter, Peter and Olivia live happily ever after. In the end, September notes Peter's disappearance.