<P> "Entrada" is the eighth episode of the third season of the American science fiction drama television series Fringe, and the 51st episode overall . The first part of the third season spent much of its time alternating between the prime and parallel universes, and "Entrada" was the first episode of the season to have time evenly divided between both . In the episode, both Olivia and her doppelganger "Fauxlivia" attempt to journey back to their respective universes . John Cassini, Seth Gabel, Ryan McDonald, Stefan Arngrim, and Karen Holness guest starred . </P> <P> Showrunners J.H. Wyman and Jeff Pinkner wrote the episode as the "culmination of a lot of things that (they) had been working on for quite a while ." Calling it one of their favorite episodes, they believed it was a good entry point for new viewers to the series . Frequent Fringe collaborator Brad Anderson returned to direct the episode . "Entrada" first aired on December 2, 2010 in the United States to an estimated 5.13 million viewers . It has been selected for "best episode" lists by various television critics . Both Anna Torv and John Noble submitted the episode for consideration at the 63rd Primetime Emmy Awards, but both failed to garner a nomination . </P> <P> At the end of the previous episode, Olivia Dunham (Anna Torv) was able to cross over back to her universe long enough to warn Peter Bishop (Joshua Jackson) she is trapped in the parallel universe . After receiving the message, Peter tests the Olivia from the other dimension, "Fauxlivia", by telling her the Greek phrase Na einai kalytero anthropo apo ton patera tou (roughly, "May he be a better person than his father"), which Olivia told Peter in the "New Day in the Old Town". When Fauxlivia fails to recognize the phrase, Peter confirms his suspicions . Realizing she has been exposed, Fauxlivia forces Peter to inject himself with a paralyzing agent . She then goes to a typewriter store in the Bronx to contact the parallel universe to request an extraction . </P> <P> After Peter recovers, the Fringe team starts a search for Fauxlivia . Walter Bishop (John Noble) is distressed that he has no idea how to find Fauxlivia and no idea how to bring Olivia back . However, Astrid Farnsworth (Jasika Nicole) discovers Fauxlivia brought Walter malasadas from a bakery in the Bronx . Peter, Walter, Farnsworth and Phillip Broyles (Lance Reddick) search the nearby area, Peter finds the typewriter store and the team finds the typewriter used to contact the other universe (a "quantum entanglement" device). There, the team realizes that Fauxlivia is going to a train station in Newark for a 4: 00 PM pick - up . </P>

When does peter find out about alternate olivia
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