Below is the official synopsis for episode one of Season 3 entitled Olivia.
After the extraordinary turn of events that shockingly left an imprisoned Olivia “over there,” she fights to find her way home. Meanwhile, Peter and Walter try to move on with their lives unknowingly alongside alternate Olivia in the “Olivia” season premiere episode.
Cast: Anna Torv as Olivia Dunham; Joshua Jackson as Peter Bishop; John Noble as Walter Bishop; Lance Reddick as Phillip Broyles; Blair Brown as Nina Sharp; Jasika Nicole as Astrid Farnsworth
Guest Cast: Andre Royo as Henry; Amy Madigan as Marilyn
Fringe Season 3 begins Thursday, September 23rd in the US and October in the UK.