When the BAU goes against a gang of serial-killing bank robbers in Washington, D.C., the team tries to negotiate the situation unfolding inside the bank, but the stakes rise when one of their own becomes a hostage. As the team determines that the suspects have a bigger target in mind in the Nation's capital, they must diffuse an explosive situation and wedding bells ring for one member of the BAU as Prentiss ponders her future. Ed Randall, Tricia Helfer, Evan Jones, Jayne Atkinson, Josh Stewart, Nicholas Brendon, and Sebastian Roche guest stars.