Liz and Jack find themselves battling to influence voters in the upcoming presidential election. Meanwhile, as Jenna goes to great lengths to please her new fan base, the writers seek out new ways to mess with her.

The gang celebrates Halloween at Stuart's comic book store. Meanwhile, Leonard seduces Penny with science.

A war breaks out between biker gangs and a bomb explodes in a suburban neighborhood. Team One tries to defuse a second bomb, and help a wounded informant.

Connor continues his search to uncover the secrets of Mystic Falls and tries to convince Jeremy to work with him. With Dr. Fell's help, Damon and Klaus question Connor, but the confrontation takes a lethal turn. Trying to keep her new life as normal as possible, Elena is determined to continue her senior year at Mystic Falls High with support from Matt and Caroline. Rebekah's arrival at school makes it difficult for Elena to control her anger, but she learns that confronting Rebekah can be extremely dangerous. Later, Rebekah realizes how alone she is, and reaches out to April. Stefan takes Elena on a thrilling motorcycle ride in an effort to show her that life can still be fun. Tyler gets a surprise visit from Hayley, a werewolf who helped him through the ordeal of breaking his sire-bond to Klaus. Concerned about Elena, as well as his own emotions, Stefan turns to a sympathetic Caroline for advice.

In an attempt to end the standoff on Sainte Marina, Marcus and Sam enter into tense negotiations with the U.S. Government. Meanwhile, when a critical system fails, Grace must take command of the Colorado on a perilous repair operation.

Walden takes Lyndsey up on her offer to set him up with some of her friends. The results are disastrous, so he decides to be alone until Rose appears.

After failing to get Chris's attention, Reagan worries that she is losing her romantic touch. A visit to the dentist gives her a much needed confidence boost. Meanwhile, when Ava learns her neighbors aren't so fond of her, she teams up with Walter to give the neighborhood a haunted house like they have never seen before.

Aware that Derek might never operate again, Meredith stops talking about the surgeries she's performing. Meanwhile, Richard calls on Dr. Catherine Avery to help him perform a complicated procedure, as things continue to heat up between Jackson and April; and Arizona's struggle to accept her fate forces Callie and Alex to face their guilt.

It's Halloween in the office and Andy invites his college a cappella group to perform, which leads to a confrontation with his frenemy Broccoli Rob. Meanwhile, Dwight finds evidence that a madman is loose in the office and tries to track him down, and the first meeting of Jim's new job causes a fight with Pam.

Reese and Finch discover that the man they've been assigned is a mob enforcer ordered to kill the wife of a dead mobster. However, they soon discover that the enforcer is in love with the woman, and have to decide rather to protect him as well or let him die.

Fourteen designers return for a second chance; the designers flaunt their fashion attitudes in a team challenge.

Iris, a Bosnian immigrant, is arrested on the suspicion of killing a judge for deporting her brother. Vincent insists that Iris is innocent, so trusting his instincts, Cat works behind-the-scenes to uncover the truth. When Cat's actions disrupt the investigation, Joe places her on leave. Nevertheless, she continues on her own to discover that Iris is hiding a family secret, and needs Vincent's help. JT is concerned that Vincent risks exposure to Murifield by helping Cat, leading Cat to work out a way to communicate with Vincent without seeking him out.

A new job offer for Ben causes Leslie to contemplates their future. Meanwhile, Ron and Andy take Diane's girls out trick-or-treating, and Tom searches for a new business idea.

Dennis and the gang crash Maureen's wedding to make certain he'll be able to sever all ties, only to discover a union much scarier than kissing cousins.

Jenni fears that her relationship with Roger is in jeopardy; Mike has second thoughts about his relationship with Paula.

A DC college student goes missing and her grieving parents come to Pope & Associates for help. Meanwhile David is still investigating the Cytron case and gets help from a very surprising source; and in the White House, Fitz feels the pressure as Mellie proves once again that she's a political powerhouse.

Even though he despises bankers, Holmes agrees to consult on a case involving the death of a Wall Street executive who appears to have overdosed on heroin. Meanwhile, with Holmes' encouragement, Watson tries to re-enter the dating scene.

Pete has a big paintball outing planned, but the married guys have to go to a kid's birthday party. Ruxin has a run in with a white sushi chef.

Rep. Nancy Pelosi

Simon Baker, Kaitlin Olson, Reggie Watts

Gov. Mitch Daniels

Donald Trump, Adam Levine, Carly Rae Jepsen

Russell Brand, Jane Lynch

The true story behind the voice of the Public Address system is discovered.

Jessie and Sam head underground to infiltrate a group of crazed book sellers who are intent on destroying the Internet.

Michael Chiklis, Maggie Grace

Julie is welcomed back to a Lorraine-free Valco but she is not her normal self. Kieran realises that he's more like Andy than he realised.

Alexander Armstrong hosts whilst Victoria Coren and Conrad Black are the guest panelists.

After forcing Jason to give Alfie a job on the sandwich run, Gemma finds herself at a self-defence class run by Tom. When an inflamed Jason gate-crashes the class he is attacked from all sides, and Billy must decide if he can carry on living under Gemma's roof.

James Cordon hosts a sports quiz show and is joined by Mo Farah and Claudia Winkleman

Stephen Fry asks for 'quite interesting' answers, this time about journalism. With Shappi Khorsandi, Ross Noble, Johnny Vegas and Alan Davies.

Graham is joined on the show by Daniel Craig, Judi Dench and Javier Bardem.

The Autobots and the Decepticons fight on Cybertron as they pursue the Omega Lock.

Part 1 of 2. Tron's history before the occupation is revealed. Meanwhile, Beck tries to convince Tron to stop his planned revenge against a program named Dyson that was once his friend.