As the girls are forced to stay in Rosewood, questions about the new mystery surface. A restless Aria starts to look suspicious as she heads back to Boston a little too quickly. But could Aria really be the one behind this? As Spencer, Emily and Hanna find themselves back in familiar territory, they aren't happy with going about solving this puzzle "the old way."

Meanwhile, Emily continues to lie about her life in California and Alison keeps a close eye on her friends.

Aria, Emily, Hanna and Spencer find themselves back in familiar territory with the Rosewood P.D. knocking at their doors looking for answers and their actions now affecting the loved ones around them. With her mother's job on the line, Hanna tries to come up with an alibi that could save all four of them with the help of her old high school friend, Lucas.

Meanwhile, Emily comes clean about the last five years, and Aria goes the extra mile to keep Ezra's second book in play with her boss.

With the Rosewood P.D. breathing down Hanna's neck about The Radley security footage, she opts to confess the truth to those closest to her in hopes they can help. Aria continues to search for answers, with help from Emily, on whether Ezra is as guilty as he seems. Spencer works together with Caleb to track down the new threat.

Meanwhile, there is awkwardness all around when new love interests emerge and old ones resurface.

In order to prove Sara Harvey is behind the threats, Team Sparia reunites to find evidence of Sara's involvement before they go to the cops. Caleb puts together a plan with Hanna to fight back against the new stalker by using the security footage tapes.

Meanwhile, Aria gets unexpected news from her family, and Ali comforts Emily in her time of need.

While new discoveries are made in the investigation of Charlotte's murder, the truth begins to emerge about the Liars' personal lives. Spencer is concerned to learn her mother is keeping a secret of her own. Aria confesses to Liam how deeply she's involved with Ezra's book. Ali admits that she and Elliott are more than just friends. Mona reveals where her true allegiances lie. Caleb, Spencer and Hanna deal with the complications of new relationships.

Meanwhile, Emily and Hanna each receive shocking threats that elevate the seriousness of the situation.

With the fallout of Hanna’s abduction still weighing heavily on the PLLs, the Liars begin to grow suspicious of Elliott Rollins as Ali’s condition worsens. Tensions rise between Liam, Aria and Ezra as they work on the book together. Spencer and Caleb are on edge, as neither of them want to talk about the awkward elephant in the room.

Meanwhile, Emily receives a disturbing phone call and tries to find a way to see Ali.