Sherlock tries to prove that one of the people whose body was found in the wreckage of a small plane crash was actually killed before the plane went down. Meanwhile, Watson tries to convince Sherlock to meet with his elusive father.

The McKinley High production of "Grease" is being cast, and Artie recruits McKinley graduates Mercedes and Mike to help out with auditions. Competitors for the lead role of Danny include Jake and football player Ryder Lynn, while Marley and cheerleader Kitty are rivals for Sandy, the female lead. Will also has a big decision to make.

In this Meredith & Cristina-centric episode, the two friends continue to cope with life after the plane crash and their ever-growing responsibilities at their respective hospitals. As Meredith juggles taking care of Zola with a case that hits close to home, Cristina assists Dr. Thomas on a challenging heart surgery.

The Gang gets Freudian as they step into the therapist's office to work through their mountain of issues, but when Dennis thinks he has everyone figured out, the shrink turns the tables on him and exposes the insanity in his unique brand of pop psychology.

Actor Robin Williams; a Top Ten List presented by Homer Simpson from "The Simpsons"; musical guest Lianne La Havas

Leslie is nervous about meeting Ben's divorced parents. Tom prepares to pitch his new business to Ron with Jean-Ralphio's help. Chris rides an emotional rollercoaster.

The Machine’s latest number sends Reese to the suburbs.

When the wife of a governor is raped, the governor takes the law into his own hands and then asks Olivia and her team to come in and clean up his mess. Meanwhile, both Cyrus and the President are caught off-guard when Cyrus' husband, James, decides to return to his career as a journalist covering the White House.

Bernadette wants Wolowitz to move out of his mom's house; Sheldon is caught in the middle of Amy and Wil Wheaton's argument.

New York experiences a nor'easter, an Albany strip club claims to sell art, platonic friends learn the scientific truth, and Rachel Maddow talks election night.

From "NCIS: Los Angeles", actor LL Cool J; from "Skyfall", actress Naomie Harris; musical performance by Sutton Foster.

Kevin runs into NFL quarterback Ryan Fitzpatrick at a charity event. Meanwhile, the guys attempt to determine who among them is the smartest.

Money problems plague Andy's family. Meanwhile, Dwight guests on a local radio show, so the staffers harass him with outrageous phone calls, and Kevin unearths a big secret about Oscar.

Stefan and Klaus form an uneasy alliance to try and contain the danger that Connor has unleashed on the town. When Connor takes Jeremy, Matt and April hostage at the Grill, Stefan and Damon have a serious disagreement about the best course of action, and Elena is again caught between the two brothers. The situation quickly turns violent when Klaus sends one of his hybrids, Dean to stand up to Connor. Caroline is surprised to find Hayley at the Lockwood mansion. Meanwhile, Professor Shane works with Bonnie to help her get past her fear and guilt.

The votes are revealed, and the coaches make their saves.