Olivia and the others of Fringe division attempt to determine the origin of Peter Bishop, who purports himself as Walter's son who had died as a young boy in the original time line.
Team captains Sean Lock and Jon Richardson thrash out the hot stories of the week, from the silly to the serious, and are joined by famous faces from the world of comedy, entertainment and showbiz, including Russell Kane, Mark Watson, Louise Redknapp and Example.
The Cats track the location of the first stone to the mystical Elephant Village, but Lion-O can't find the specific location and the forgetful Elephants no longer remember where it is.
General Krell orders Captain Rex and the clone troopers of the 501st Legion to conquer a heavily fortified Umbaran airbase, and will not accept anything less than victory. It is an almost certain suicide mission, unless the clones can use their ingenuity to defeat their new enemy.
Frank deals with a political crisis after Jamie and Renzulli are injured by a church security team that refuses to let them enter a religious center in response to a 911 call.
As the team takes on a missing persons case, Chuck and company struggle to establish themselves as Carmichael Industries in the face of a rival security firm led by the tough and efficient Gertrude Verbanski. Meanwhile, Morgan continues to adjust to the Intersect while Chuck adjusts to being his handler. Also, the Buy More finds an unlikely spokesperson to help drum up business.
A barbaric family history is revealed when Nick and Hank investigate a case of breaking and entering. Meanwhile, Nick assigns Monroe to look after Aunt Marie.
While in prison, Ryan Fletcher discovers patterns that reveal how Oversight gets its funding. Ryan arranges a meeting with Nikita to fill her in, but Amanda intercepts their coded messages to each other and alerts Oversight, who sends in one of their own to interrogate Ryan. Nikita and Michael scramble to break Ryan out of prison before Oversight gets to him. Meanwhile, Alex is being tailed by Gogol, and comes face to face with someone from her past.
A local Pawnee group predicts the end of days, causing chaos in the Parks department.
With help from Elena and Bonnie, Alaric tries to decipher the meaning behind his recent discovery Elena and Rebekah engage in a mean-girl power struggle, until Rebekah finally reveals some of her family's ancient secrets and the violent past she shares with Klaus and Elijah. Damon tries a reckless new approach to make a breakthrough with Stefan, and they're both surprised by an unlikely ally.
The doctors become nostalgic when George O'Malley's mother, Louise, returns to Seattle Grace for medical help after a botched surgery at a neighboring hospital; the residents are inspired by a medical miracle when they witness a harvested heart that continues to beat outside the body; a new pediatric fellow excites Arizona and makes Alex feel threatened; Jackson lets his suspicions about Mark and Lexie interfere with his work; and Henry and Teddy have their first marital fight when he expresses interest in pursuing medical school
Amy becomes heartbroken when she discovers that Penny and Bernadette went wedding dress shopping without her.
The gang uses the Internet to cyber-stalk their prey. Frank tries to drum up business for Paddy's with a viral video.
When a drag queen's song makes Hawthorne Wipes an iconic gay product, Pierce embraces it, until his homophobic dad shows up to squelch the idea.
Michael and Fiona plan to abduct a hacker in Puerto Rico in order to obtain his software, but the man has several other enemies to contend with. Elsewhere, Madeline learns to retrieve information from the police under the tutelage of Sam and Jesse.
The search for a serial killer hits close to home for Jane when he encounters a blogger who has devoted his life to finding the killer.
After not hearing from her grandmother for a couple of days, Cassie becomes concerned and wants to go look for her. Diana decides the entire Circle should go in case Jane is in trouble. She also invites Jake along, much to Adam's dismay. A storm turns the day trip into an overnight excursion, so Faye suggests a little game of Truth or Dare to liven up the evening. However, things take a horrible turn when Faye is forced to reckon with someone from her past.
The Machine identifies a school teacher who witnessed a mob hit as their next POI and Reese and Finch rush to save his life.