In the wake of Nolan’s murder, Ava, Caitlin and Dylan join forces to give themselves a credible alibi on the night in question. Alison goes toe to toe with Dana Booker, BHU’s new head of security, who is suspicious of Nolan’s “perfect” posse. And Mona starts slipping into old habits while wrestling with a guilty conscience.

The Perfectionists kick their investigating into high gear when they identify a possible suspect in Nolan’s murder. Alison begins to look into the circumstances surrounding the mysterious suicide of Taylor Hotchkiss. And seeing the Perfectionists juggle sleuthing with their intense academic demands, Alison decides to use her past in Rosewood as a way to mentor them through their current situation.

Alison hunts for Taylor, thinking she may be alive and in hiding. Caitlin, Ava and Dylan realize their newfound true friendship is threatened by still buried secrets and debate coming clean to each other. And the Perfectionists try to tighten a noose around their number one suspect.

Mona communicates with a mysterious stranger who promises insights into Nolan’s murder. Dylan struggles to concentrate on an important audition while being distracted by Dana Booker’s investigation. And the Perfectionists plan to clear their names ends in tragedy.

When Alison brings Mona into her investigation of Taylor, Mona makes a surprising discovery. While preparing for the campus fashion show, Ava comes into contact with Zach, a fellow student with an unexpected connection to her past. And the Perfectionists struggle to recover from recent events.

During BHU's Dead Week, Caitlin tries to get her academic life in order, as well as elevate her relationship with Jeremy. Ava reluctantly teams up with Zach on a school assignment and Dylan's nerve damage impacts an important music project. Ali continues to make inroads with Taylor, while Mona investigates who left her a mysterious message.

Mona, Ali and the Perfectionists concoct a plan to turn the tables on Dana Booker. Ali and Mona separately try to deduce how much they can trust Taylor as part of their team. Caitlin is left reeling when she finds out Jeremy may be keeping secrets of his own.

On the night of a school gala, the gang is convinced they know who killed Nolan and set out to prove it. However, Dana continues to complicate their lives by exposing a critical secret between the Perfectionists.

In the aftermath of a shocking event, Ali, Mona and the Perfectionists try to pick up the pieces of their lives. However, new information is uncovered which makes them question everything they think they know.