Halloween provides the scenario when the BAU is called to Dallas to assist in the investigation of women who became victims of a man they'd met through a dating service and then rejected him.
A serial killer is executed, in Oklahoma, a copycat shows up and the BAU are called to find him. Meanwhile, Prentiss gets nervous about a real estate purchase.
When the BAU goes up 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 BAU team continues to pursue the bank-robbing serial killers, the team determines that the suspects have a bigger target in the Nation's capital, and with one of the team still a hostage, they must work quickly to diffuse an explosive situation. Also, wedding bells ring for one of the BAU, and Prentiss ponders her future.
An elite team of FBI profilers analyze the country's most twisted criminal minds, anticipating their next moves before they strike again. The Behavioral Analysis Unit's most experienced agent is David Rossi, a founding member of the BAU who returns to help the team solve new cases.