The girls are reunited when they each begin receiving threatening messages from someone named "A," suggesting Alison is actually alive - and watching them.

Hanna worries that her mother is keeping a dangerous secret and is determined to protect her at all costs, which leads to an uncomfortable meeting with Detective Holbrook.

Holbrook's partner, Lt Tanner, comes to town, intensifying their investigation into the Liars and their possible connection to Wilden's death.

Hanna's interest in crime novels helps her to come up with a plan to figure out whose body is in Ali's grave. Spencer is working overtime to decipher the stories in Ali's diary.

With Spencer's possible revelation about Board Shorts, she is now more determined than ever to prove her theory before bringing it to the other girls' attention.

The Liars are concerned for Aria as they watch her crumble after learning shocking news about Ezra. Not knowing what is true or who to trust, Aria goes looking for answers.

Emily takes up the sleuthing reins as she searches for answers about Ezra and Mona. After confronting both, Emily tries to make sense of the heartbreaking situation.

Spencer is reeling about the memories from her 'lost summer', Aria is nursing a broken heart, Emily struggles with Paige's betrayal and Hanna attempts to get back into dating.

After years of questions and mystery surrounding the night Alison DiLaurentis disappeared, The Liars finally learn what really happened to her that September night.

Aria watches over Ezra at the hospital, while Alison and the others set a trap for "A."

Emily, Spencer and Hanna try to adjust to the new normal; Kenneth searches for Jessica.

Aria, Emily, Hanna and Spencer feel trapped and search desperately for a way out of a bad situation.

A Halloween-themed ode to viewers features interviews with cast and crew, fan questions and visits from dearly departed characters.

The girls are not feeling merry at Christmas because Spencer's murder charge looms over them. Things improve though after they see an opportunity to gather evidence to clear her name.

Mona's friend comes to town to pay her respects.

Aria hopes Andrew can be her tutor; Spencer helps Jonny with a new project.