First Aired: Apr. 01, 2010 on FOX
Summary: While explaining Peter's other-worldly beginnings to Olivia, Walter flashes back to 1985. Peter's mother is introduced and more details about "the other side" come to light.
Main Characters in this Episode
Dr. Walter Bishop: There's only room for one God in this lab, and it's not yours.
- When two of of the observers go to see the movie Back to the Future, there is also a poster for the movie Clue hanging at the theater. The title ("Olivia. In the Lab. With the Revolver") and the contents of the next episode references the mystery board game "Clue" on which this movie was based. Clue is also the game that Sam brings to Olivia's apartment to play with her in the middle of the night in that next episode.
- When the movie theatre from the alternate universe is seen, it is showing "Back to the Future: starring Eric Stoltz". In fact, Stoltz did play Marty McFly in Back to the Future for a few weeks. Michael J. Fox was originally unavailable, so Stoltz did some filming, but realized that the part was not right for him. By that time, Fox had become available and did the movie.
- On the DVD commentary, Blair Brown says that to create her "1985" hairstyle for the flashback scenes, she brought in to the hairstylists some pictures of herself from Continental Divide, and the hairstyle she had in that actual 1980s movie is the model they used to cut the wig for younger Nina's hair.
- This is the first episode to not feature Joshua Jackson, apart for a small clip from a previous episode.