Fringe: Peter

"Peter" is the 16th episode of the second season of the American science fiction drama television series Fringe, and the 36th episode overall. Considered a keystone installment of the series, "Peter" is a flashback episode, told as Walter Bishop (John Noble) reveals to Olivia Dunham (Anna Torv) that his son Peter (Joshua Jackson) is really the Peter of the parallel universe. Walter explains the events that occurred in 1985 that led to this, and the impact it had on the parallel universe to be at war with the prime one. The episode's story was written by Akiva Goldsman, J. H. Wyman, Jeff Pinkner, and Josh Singer. Its teleplay was written by Pinkner, Wyman, and Singer. David Straiton directed the episode. It was guest star Orla Brady's first appearance as Walter's wife Elizabeth. "Peter" first aired in the United States on April 1, 2010. An estimated 5.8 million viewers watched the episode, giving it a 2.2 rating share among those 18–49. The episode received almost overwhelmingly positive reviews, with numerous critics considering it to be the best Fringe episode to date. Actor John Noble was lauded for his performance, and "Peter" topped many "best of television" lists for the year. It was ranked the best episode of the entire series by IGN and Den of Geek and the second best by Entertainment Weekly.