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.