When dealing with matters of the heart, people react in many different ways: Still crushed over her break-up, Spencer continues her downward spiral as she now takes her anger and hurt out on Mona. Caleb, on the other hand, hides his pain by being closed off when discussing his father. But when Hanna devises a plan to bring father and son back together, will that help Caleb heal old wounds or just make things harder? And Aria, who is still missing Ezra, finds she is spending more time with Wes. Meanwhile, Emily and Jason work together to put together the pieces of Ali's trip to Cape May and what really happened during that vacation.

Secrets abound for Aria, Hanna and Spencer while Emily tries to let go of Paige.

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.