Lindsay calls on Voight and his unit for help with her first case on the federal task force; Burgess is relegated to desk duty.
Stiles is locked up while the rest try to figure out whether or not they need to sacrifice Stiles to get rid of the Nogitsune.
With her impending death, 500-year-old Katherine reminisces about her life and the night she gave birth in 1490. Stefan informs Elena, Caroline and Bonnie that Katherine doesn't have long to live. Damon, Matt and Jeremy talk about Katherine's infamous moments. Stefan and Elena are forced to help Nadia save her mother. Caroline indulges in some scandalous behavior. Katherine and Elena share a moment of bonding.moreless
While Peter and Derek try to save Cora's life in the aftermath of the storm, Stiles works frantically on a plan to prevent his father and Scott's mother from becoming Darach's next victims. Ultimately, there's a difficult choice to be made that could endanger everyone's lives and change them forever.moreless
Allison becomes increasingly suspicious that her father is up to no good.
The Darach has targeted Healers for another set of sacrifices and Dr. Deaton is one of them. The Alpha Pack again threatens Derek and his Pack, this time with a more dire outcome.moreless
The battle between Derek's pack and the Alpha pack brings about serious repercussions.
A friend of Stiles vanishes while Lydia and Allison discover a hint as to the location of Boyd and Erica.
J.T. thinks that Catherine's presence has been causing Vincent's blackouts. Hoping to prove J.T. wrong, Vincent has J.T. inject him with endorphins and sedatives that trigger a fugue state. In flashback, Vincent sees his time in Afghanistan when he received his first dose of the medication and remembers the doctor who injected him with the DNA-altering substance. Vincent also recalls how the other soldiers suffered from unpredictable side effects, including fugue states, and is relieved to know that Cat isn't triggering his blackouts. Vincent tells Catherine about his memories about Murifield, and she remembers a few pieces of information. As Cat and Tennis investigate the attempted shooting of a teen pop star, Evan starts to suspects that Cat is protecting the vigilante who saved him in the subway.moreless
Maya's trial gets underway, and Emily can't stand the media attention. "A" then extends a branch to the girls, who are skeptical; and someone close to the girls betrays them.
Hanna and Emily try to figure out clues about Maya at the Kahns' cabin in the woods. Meanwhile, Spencer investigates Noel; and Aria tries to understand what she's learned about Ezra's background.
The time is ticking as Scott tries to find out Gerard's master plan following a death on campus.
Hanna receives yet another text message from "A" concerning Caleb. Elsewhere, Aria and Spencer head to the Kahn brothers' party to confront Jenna about her truthfulness.
Scott has to pull double duty by playing in the championship lacrosse game and finding a way to stop Gerard.
Emily tries to figure out what happened the night she was drugged and also tries to fix things with Paige. Ezra's mom gives insight into Ezra's past to Aria. Spencer and Caleb hack a website for Mona and Hanna also tries to help out.moreless
With the new shape-shifter on the loose, Scott and Stiles try to devise a plan to trap it. Meanwhile, Mrs. Argent sets out to deal with Scott once and for all.
Derek is sure that Lydia is the shape-shifter, and asks Scott to help him find out. Meanwhile things develop with Jackson, as the bite begins to show promising effects. The shape-shifter could possibly be a woman.moreless
The shape-shifter continues his murders while Scott tries to get Allison to retrieve a rare book in Gerard's collection
As Aria discovers what Holden's secret is, Caleb becomes the target of a Rosewood Police Department witch hunt after his laptop is confiscated.
In A Kiss Before Lying, Caleb is working with Hanna's three best friends to decode video from the night of Alison's murder. Meanwhile, Hanna's evil step-sister, Kate, is enrolling at the same high school. Caleb discovers that Alison had a second fake ID, and in this one she has dark hair, which opens up a whole new line of questions.moreless
When Lucas goes missing Caleb searches tenaciously while Hanna hesitates because she doesn't want it to lead to Caleb's discovery of "A".
A family recovering from a mother's miscarriage, and a father's infidelities make the decision to move into a creepy home with a complicated history. The family is introduced to a handful of eccentric characters including a psychopathic teen patient of the father, a mysterious housekeeper who isn't what she seems, a former resident of the home who murdered his family, and a southern actress with a disturbed daughter.moreless
Aria, Emily, Hanna and Spencer finally decide it is time to tell someone about "A." Meanwhile, Hanna's infamous grandmother drops into town for Tom's rehearsal dinner.
The four liars remember a frat party and question Alison's motives that night. Aria uses the school play as a means to get closer to Ezra. Hanna and Caleb are pushed to a new level in their relationship. Spencer and Toby become closer. Emily shares some new information and 'A' watches everything closely.moreless
The Rosewood Sharks have an important swim meet and Emily encounters Paige again. Caleb uses his favor from Hanna, who tries to keep Aria from becoming suspicious of her over of Ella's museum ticket. A past enemy may not be just so.moreless
"A" persuades Hanna to return to her law-breaking ways. Meanwhile, Noel continues to bait Ezra, Emily's mother makes clear her dislike of Emily and Maya's relationship, Spencer adjusts to Melissa's sudden marriage, and the girls get help from a surprising place.moreless