Trace the journey from 9/11 to the Boston Marathon bombings and investigate the secret history of the battle against terrorism.

In the aftermath of the Boston Marathon bombings, the threat of terrorism again confronts Americans. More than a decade after 9/11 and hundreds of billions of dollars later, there are pressing questions about whether America’s investment in its “terrorism industrial complex” has made us safer. In FRONTLINE’s “Top Secret America,” Pulitzer Prize-winning reporter Dana Priest traces the journey from 9/11 to the Boston Marathon bombings and investigates the secret history of the 12-year battle against terrorism.