Tracy and Jack engage in a battle of wits after Tracy depicts Jack as a villain in his latest project. On Jack's advice, Liz puts her own needs ahead of those of "TGS". Meanwhile, Jenna tries to shield Kenneth from Hazel's manipulation but her own selfishness gets in the way.

Howard and Raj try to get to the bottom of why Sheldon disappears every afternoon at 2:45. Meanwhile, Leonard and Penny deal with jealousy in their relationship.

Sons of Parker and Ed join Team One on a routine call. A shootout changes the situation though, making circumstances much more dangerous.

Terrifying hallucinations leave Elena shaken and confused, causing her to make a dangerous mistake. After giving Stefan some very disturbing news about Elena, Klaus takes matters into his own hands. Professor Shane reveals a story of ancient witchcraft to Damon and Bonnie. With help from Klaus and Stefan, Jeremy begins a new chapter in his life. Finally, Elena makes a painful personal confession to Stefan, and Matt gives Damon startling new information about Professor Shane.

Results Night and Demi Lovato and the Young Adults: Paige Thomas, Jennel Garcia and CeCe Frey, L.A. Reid and The Over 25s: Vino Alan and Tate Stevens, Simon Cowell and the Groups: "Lyric145", "Fifth Harmony" and "Emblem3" and Britney Spears and the Teens: Arin Ray, Beatrice Miller, Carly Rose Sonenclar and Diamond White wait to see if they did enough. Musical Guest: Taylor Swift.

As Marcus and Sam hunt for the traitor in their ranks who stole their nuclear launch key, Prosser disobeys orders and starts a small war he can't control. Meanwhile Grace and James must work together to defuse a dangerous situation, as back in D.C. Christine is indicted as Sam's co-conspirator.

Lyndsey draws a line in the sand regarding her commitment to Alan and he struggles with his decision. Walden becomes a boy-toy.

After their flight is cancelled, Chris and Reagan are forced stay home for Thanksgiving.

As the doctors continue with their lawsuit, they're forced to confront the realities of their injuries. Meanwhile, Bailey tricks Arizona into helping her with a pediatric case, and Cristina tries to find normalcy in her new environment.

Dwight faces his greatest professional shortcoming - selling to women. As a result, the lady staffers step up to give him advice so he can successfully sell to an important female client. Meanwhile, Angela suspects her paramour is cheating; Andy uses technology to connect with the others from his boat; and Toby tries to convince the men to grow mustaches.

The McKinley High production of "Grease" opens, and Santana returns to help out. Rachel has another run-in with Cassandra, her dance instructor; and Kurt and Rachel visit Lima. Finn becomes the interim Glee Club Director.

The Machine directs Finch and Reese first to Leon Tao, who has gotten in trouble again, and then to a doctor who is being forced to kill a patient to save her wife.

Fashion meets social media when images submitted by newspaper readers inspire the all-star clothiers' looks. Designer Charlotte Ronson and fashion blogger Tavi Gevinson are the guest judges.

After she's seemingly stood up by Vincent, Catherine wonders if it's because he saw her kissing Evan at her birthday. Actually, Vincent mysteriously blacked out on his way to meet Catherine, and is now searching for answers. Catherine's case pulls her into the sophisticated world of the SoHo art scene. When Vincent finds Catherine all dressed up to go to a gallery opening - with Evan - he has to admit that his feelings for her are growing deeper. All the while Evan makes his affections for Catherine known, leaving Catherine torn between the two very different suitors.

Leslie gets upset when April tries to get Lot 48 made into a dog park. Meanwhile, Tom enlists Ben's help as he tries to launch his new business venture, and Andy hones his crime scene investigation skills.

Mac, Charlie and Dee struggle with their faith as Charlie's mom fights cancer. Meanwhile, Frank loses his memory amidst a search for buried treasure.

Michael becomes the target of a CIA task force after he's accused of a crime at a local hotel. Meanwhile, senior officer Olivia Riley brings Sam in for questioning, and attempts to use him to find Michael's whereabouts.

Jenni plans a shower for Snooki; the guys support Mike's decision to break up with Paula.

Olivia receives an anonymous letter containing a coded warning which could expose Huck's dark past. Meanwhile another Pope & Associates secret has already been exposed and Olivia asks Harrison to step up and handle it. And in the White House, Cyrus and Fitz are dealing with the ramifications of Cyrus' husband's first front page news story.

Sherlock assists with a double homicide that has the same M.O. as a series of murders that took place 13 years ago. Meanwhile, after being frozen out by Sherlock, Watson visits his old rehab center in order to learn more about the mysterious man in her care.

Andre's plan to take the guys tailgating is thwarted when their high school nemesis Frank "The Body" Gibiatti and his gang have the same idea. Taco tries to sell knockoff merchandise and has a run in with Chicago Great Jim McMahon.

Andrew Napolitano

Kellan Lutz, Jimmy Pardo, Jeff the Brotherhood

Chris Stringer

Zooey Deschanel, Lisa Lampanelli

Tim Allen, Nolan Gould, Switchfoot

An episode of Newsreaders takes a look at the death of a cast member.

Max Greenfield, Lucy Punch

Julie and Gavin are feeling giddy about the one-millionth-customer promotion. Lisa ends up telling Colin how she feels.

Olympic 2012 champion and all-round golden girl Jessica Ennis and comedians Micky Flanagan and Jimmy Carr stop by the studio for this episode of the sports-based quiz.