After their latest run-in with Charles, tensions are at an all-time high with the PLLs and the town of Rosewood. Aria’s big moment of seeing her work displayed in an art gallery is in jeopardy as Ella is determined to keep her safe at home. Hanna is still uncomfortable with the unexpected scholarship money and is determined to give it back, even if that means ruining her chances at going to her school of choice. And to top it off, the one normal high-school rite of passage the girls are looking forward to is in danger as Rosewood High is considering not letting the PLLs attend prom due to security issues.

Meanwhile, the more Alison learns about her brother the harder she finds it to connect a deranged murderer to the young blonde haired boy she sees in the photos and in her memories.

It is prom time at Rosewood High School, except for Alison, Aria, Emily, Hanna and Spencer who have been banned due to "security" concerns. As the girls see this as the final humiliating blow to their high school careers, the girls' mothers try to make the best of a bad situation by offering a home prom in Spencer's barn. At first reluctant, the PLLs agree and try to make the best out of a bad situation. But one to never miss a formal, Charles has other plans in store to make this a night they will never forget.

Meanwhile, Veronica, Pam, Ashley and Ella use prom night to touch base on everything that has happened to their daughters.