Tina goes undercover in her old Thundergirls troop to find the mole who is giving away their cookie secrets. Meanwhile, Linda dyes her hair blonde.

Jake and Charles’ bro-mance starts to crack when they volunteer for an eight-day stakeout in very close quarters. Meanwhile, Captain Holt’s nephew, Marcus, comes to Brooklyn and captures Rosa’s attention.

The CSI team investigates the bizarre death of a man who was killed not once, but twice.

Carrie puts her life on the line to get her team out of Pakistan.

Bo needs the help of an estranged family member. Lauren finds herself haunted by a mysterious spirit.

In the aftermath of the Snow Queen’s spell, our heroes try to pick up the pieces and Regina has to make a difficult choice. Hook’s fate hangs in the balance as Gold’s quest for power threatens everything he holds dear. And, in the Enchanted Forest flashback, an intrusion during Belle's stay at Rumplestiltskin's dark castle will wreak havoc in both the past and the future.

A revelation about their daughter Whitney makes Noah and Helen realize their troubled marriage is directly affecting their children. Bending under remorse, Alison spirals towards a reckoning.

The Librarians' first solo mission hits a snag when Baird loses the others in a mysterious labyrinth that magically exists below the skyscraper of a modern corporation.

Jane and Lisbon travel to Beirut where they must work with Jane's familiar adversary Erica Flynn, who agrees to help the FBI apprehend her boyfriend, a courier for terrorist organizations, in exchange for amnesty for her past crimes.

Series Finale: A sudden death leads Will and Mac to ponder the milestones that transformed the newsroom, and look ahead towards ACN's uncertain future. Maggie lands a field-producer interview in Washington; Neal's digital site is shut down for repairs; Leona offers sage advice to Pruit.