Subject 13

"Subject 13" is the 15th episode of the third season of the American science fiction drama television series Fringe, and the 58th episode overall. Inspired by fan reaction to the show's previous flashback episode, "Peter", "Subject 13" occurs 25 years before the show's current timeline, in 1985 a few months after "Peter". The episode, with scenes set in both the prime and the parallel universe, explore Walter and Elizabeth Bishop's attempts to return Peter to the parallel universe using the Cortexiphan-induced abilities of young Olivia Dunham, while Walternate in the parallel universe struggles to deal with the kidnapping of his son.

Subject 13

"Subject 13" is the 15th episode of the third season of the American science fiction drama television series Fringe, and the 58th episode overall. Inspired by fan reaction to the show's previous flashback episode, "Peter", "Subject 13" occurs 25 years before the show's current timeline, in 1985 a few months after "Peter". The episode, with scenes set in both the prime and the parallel universe, explore Walter and Elizabeth Bishop's attempts to return Peter to the parallel universe using the Cortexiphan-induced abilities of young Olivia Dunham, while Walternate in the parallel universe struggles to deal with the kidnapping of his son.