Sherlock is reunited with "M." a British criminal who appears to have followed Sherlock to New York. Meanwhile, Joan has reservations about leaving Sherlock and taking on a new client.

Bailey puts her wedding day on hold and continues her efforts to save Adele's life, Cristina and Owen remain undecided about their pending divorce, while Arizona and Callie try to get their spark back. Meanwhile, the hospital becomes inundated with a group of bikers after a horrible accident.

Actor Michael J. Fox; from "Girls", actress Lena Dunham.

Carter tries to help Reese by engaging in mental warfare with the FBI; Reese has encounters with old and new enemies; Detective Fusco must protect supermodel Karolina Kurkova, the latest person of interest.

With Huck being held under the Patriot Act, Olivia and the team get unexpected assistance from an old friend. Meanwhile, Olivia helps Mellie out of a very compromising situation that could affect Fitz's future, and her relationship with Edison reaches a boiling point.

As the guys don costumes and go on a road trip to a comic book convention, the ladies decide to stay home and try to interpret a comic book.

A man makes love to a couch, Obama flaunts his testosterone-filled Cabinet, Kevin Garnett hassles Carmelo Anthony, and musician Ben Gibbard grows up.

From "Last Man Standing", actor Tim Allen; comic Margaret Cho.

Pam accidentally brings lice into the office and lets Meredith take the fall, while Dwight vows to destroy the parasites. Meanwhile, Jim has a fantastic day in Philly wooing a potential business associate, and Phyllis, Nellie and Kevin meddle in Darryl's love life.