Dalila Ali Rajah

As Jess’ job search kicks into high gear, the guys fear her time of the month is also affecting their physical and psychological well-being. Meanwhile, Schmidt begins a “50 Shades of Grey”-type of relationship with his corporate boss (guest star Carla Gugino), and Nick gains wisdom from an unlikely, hands-on (and mute) source.

The BAU takes charge of a hostage situation at a law firm in D.C., where Matt Simmons' wife, Kristy (Kelly Frye), works.

A team of doctors try to save the life of a political figure from the Middle East; Cristina decides to decorate her new place and throw a housewarming party; Alex shows up late to his first day of rounds with the new pediatrics attending.

It's Christmas in BlueBell. In flashbacks, we learn some of Lemon's history, including the details of when Lemon and Lavon first realized they had a connection.

When a missing MI6 Officer is linked to a murdered petty officer, Gibbs sends Quinn and Bishop to Philadelphia to work with MI6 Officer Clayton Reeves (Duane Henry). Also, Quinn painfully recounts the NCIS case that made her leave field work. Tony Gonzalez, former NFL player and studio analyst for "The NFL Today," guest stars as NCIS Special Agent Tony Francis.

Team Scorpion heads to Northeast Africa where they must carefully navigate a minefield in order to save the lives of local villagers. Also, Paige and Walter’s relationship takes a shocking turn, and Toby and Happy make an important decision, on the fourth season finale.