Feeling inferior to, and looked-down upon by, the new neighbors, Carrie tries to make a good impression, but Doug couldn't care less. Meanwhile, Arthur tries to use Spence for free subway rides.

Doug and Carrie are having fun on their vacation with their neighbors in St. Croix, but once Arthur calls with a quote on the current mold problem in the house, all is not so fun.

Celebrity author Walter Briggs (guest star Robert Vaughn) is the focus of a feud between his sixth wife, Charmaine (guest star Marcia Cross), and his daughters from previous marriages (guest stars Emily Bergl and Susan Pourfar). The fight over control for both his well-being and his estate becomes a criminal case when Charmaine is accused of abusing her husband. Meanwhile, Barba (Raul Esparza) struggles with his own family drama when he goes against his grandmother's wishes.

Kramer gets into meat slicing; Jerry dates a doctor (Marcia Cross) who isn't impressed with his job; George's new boss is a former adversary.

Sam tries to reconcile Rebecca and her sister.

On Cory and Topanga's wedding day, Shawn drops out as best man after he and Cory get into a fight.

The CSI team is called in when a famous real estate entrepreneur is found dead in a hotel elevator.

Cory tries to get over his break up with Topanga by dating a new girl and becoming the new Penguin mascot.

Cory and Shawn try to convince Topanga's parents to reconcile; Eric and Jack make a desperate attempt to get their apartment back.

The terrorists responsible for the bombing of Grand Central Station finally reveal themselves, but instead of answers, more questions remain. While back at Quantico, the recruits receive a well-deserved few days off for the holidays, but not everyone is oh so merry when secrets are revealed and lines and blurred.

Alex finds herself in the middle of a congressional hearing to testify about the terrorist bombings. Convinced Elias didn't act alone, she is determined to find answers and the truth. While back at Quantico, a new group of NATS join Alex and her classmates, causing tension and competition between the groups of trainees.

A terror cell tries to infiltrate Quantico, forcing Miranda and Liam to pay a deadly price. Meanwhile, in the future, Alex continues to get instructions from the terrorist, with Claire Haas' life hanging in the balance.

At Quantico, the NATS are given a training exercise that hits too close to home for Shelby. While in the future, Alex finds an unlikely ally in Hannah, as she continues to try and stop the terrorist from striking again.

At Quantico, the NATs check each other's background to determine who gets high-level security clearance, and in the process Alex, Shelby and Iris learn surprising truths about Drew, Will and Caleb. Meanwhile, in the future, Alex contacts Claire Haas in order to find her missing friends and discovers what happened to Caleb.

It's graduation day for the NATS of Quantico, while, in the future, Alex and her team find themselves head-to-head with the terrorist.

The NATS are excited that graduation is near as they prepare to leave Quantico and head out into the real world for their new assignments. In the future, Alex learns someone she cared about at Quantico is not who they seemed to be, as she finds herself at the heart of another possible attack.

Angela and Mona (Judith Light, Katherine Helmond) argue about a possible corporate takeover at the ad agency. With Tony Danza.

At the Farm, Owen teaches the trainees about enhanced interrogation techniques, and turns the tables on his students by putting himself in the hot seat. Meanwhile, Shelby goes undercover, and in the future, a new president is sworn in.

At the Farm, Owen teaches the recruits a lesson on the necessity of betrayal, with a mission of getting the Venezuelan Consul to turn on his country. In the future, Alex teams up with Miranda to save the hostages, while President Claire Haas has a plan to end the crisis.

In the wake of the G20 hostage crisis, President Claire Haas assembles an illegal and clandestine joint task force, bringing together Alex and her friends from both the FBI and CIA to unmask a global conspiracy.