It is prom time at Rosewood High, 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.