Avsnitt 1

When two bombs cut a swathe of death and destruction through the crowd of runners and spectators at the finish line of the Boston Marathon, the FBI steps up to lead a massive manhunt for the perpetrators. As the nation watches transfixed, the Bureau and its law enforcement partners work against time to find the bombers before they can strike again . When the suspects finally emerge, they lead authorities on a deadly high-stakes chase through the streets of Boston.