The Countess is reunited with her one true love. Donovan and Ramona take another stab at revenge. A careless decision lands Alex in hot water.

After the city is attacked again, Oliver makes a bold move against HIVE. Malcolm checks in on Thea and leaves her with a warning. Things take a horrible turn when Damien Darhk retaliates in a brutal manner at Oliver’s mayoral holiday party.

Dre thinks Christmas has become commercialized and is all about “stuff,” and no one loves “stuff” more than his kids. Pops and Ruby think they have forgotten the true meaning of Christmas and come up with a new plan to pare down gifts and spend more time together. The kids don’t handle the news well and hope that if they put on their best behavior Dre and Bow will cave in. Meanwhile, Daphne Lido, who is single for her first holiday alone, invites herself to the Johnson family home to celebrate with them.

Leanne, Neal, Christa, Angus, Mario, Malaya, and Heather are sent to the scene of a multi-car collision on a canyon road above Los Angeles. Leanne clashes with the physician in charge, making a decision he questions. Christa treats an injured family whose car is in a ravine. Angus, Heather, and Mario help a man stuck in cement. Mario and Heather find their lives in danger when a patient's husband holds them at gunpoint to save his wife. Meanwhile, Jesse recovers from his heart attack.

The BAU searches for an UnSub who may be fascinated with medical experimentation.

Christina searches for new living arrangements, Lisa realizes Alvey's home may not be the place for her, and Ryan and Jay cut weight as their respective title fights loom.

Gloria’s plans for a White Christmas don’t go as planned.

It's a big morning for Markus Keen when "Good Morning America" comes to Nashville to broadcast a live concert in support of his new album launch, but come show time, Markus finds he's anything but ready. Meanwhile, Luke's relationship with Colt continues to be strained while Luke learns of another setback to launching his brand. And living in the same house, but feeling further apart than ever, Rayna and Deacon face a big decision.

The gentrification of South Park is pricing Randy right out of town. Meanwhile, Kyle’s distrust of Stan has broken their friendship and thrown Kyle into a dangerous alliance.

Amara unleashes her power on the local townspeople as she issues a shocking challenge. Dean tries to better understand the hold Amara has on him, while Sam and Crowley come up with a plan that could have disastrous consequences.

In the series finale, the fates of the Shiva, Sacko and Snip are decided and Ruxin makes a big decision that impacts his chances of winning and the league's survival.

Dreading the fact that they are always late to church and end up in the overflow room, Frankie makes the decision to have the family watch a Christmas Eve service on TV from the comfort of the Heck house. But a string of events make their evening anything but a peaceful, silent night.

There are dark days ahead…

Amy Poehler (Sisters (2015)); Kevin Nealon performs stand-up and is interviewed. Also: Lalah Hathaway sits in with The Roots.

Jimmy attends Becca and Vernon’s baby gender reveal party. Gretchen takes care of some unfinished business. Edgar and Dorothy’s relationship reaches a turning point. Lindsay confronts Paul.