High school seniors Aria, Emily, Hanna, and Spencer have been tortured by A for too long. Now they're determined to take the fight to A . . . even if it's the last thing they do.

As the rest of Rosewood prepares for the prom, the girls drop everything in their hunt for A. But with each new piece of evidence, A only seems farther away. No matter how close the liars get, A is always one step ahead -and ready to crush them completely.