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.

In the tense hours following the bombings, Sergeant John MacLellan heads out on his night shift. That same evening, an MIT police officer is murdered by two attackers. No one knows yet that the cop killers and the bombers are one and the same, and Sgt. MacLellan comes face to face with the perpetrators. The shootout that ensues leads to a citywide manhunt.

Two FBI agents go undercover to infiltrate a dangerous criminal motorcycle gang. The Outlaws – archrivals of the infamous Hells Angels – are running wild in Taunton, Massachusetts, bringing drugs and violence to the formerly peaceful town. The stakes are high as the agents plan a daring takedown. Will they make a big bust or will their cover get blown?

When an armed bank robber terrorizes the Boston area, the violent holdups leave bank employees and customers fearing for their lives. Without any solid leads, the FBI's Bank Robbery Task Force must use all its resources to catch the perpetrator in the act. But can law enforcement catch up to the Southside Bandit before the situation turns deadly?

Rumors swirled for years that two former NYPD detectives, Stephen Caracappa and Louis Eppolito were working for the Mafia, committing crimes that included murder, kidnapping and money laundering for their mob bosses. Both men retire from the police department and move to Las Vegas, but when a former Mafia underboss admits that Caracappa and Eppolitto carried out a number of murders on his orders, the FBI formulates a plan to bring the “Mob Cops” to justice.

An early-morning explosion at a federal building in downtown Oklahoma City kills and injures hundreds. FBI investigators quickly determine that the building has been bombed. The Bureau coordinates a complex rescue mission to save survivors of the blast. At the same time, agents comb through the wreckage, searching for clues about the bomber.

The FBI learns Timothy McVeigh hopes to instigate a civil war in America with his bombing of the Federal building in Oklahoma City. His arrest will set in motion a nationwide hunt that will take investigators from Oklahoma across the country, questioning collaborators, uncovering evidence and unveiling the history of a young man disillusioned with the government.

In one of the most infamous serial killer cases in American history, the FBI works with local law enforcement in California to try and apprehend the so-called “Golden State Killer.” It’s a case that spans four decades, as the killer and rapist continually manages to elude law enforcement. Authorities resort to an unprecedented use of DNA data in an attempt to finally track down the man responsible for 13 murders and 51 sexual assaults.

Masked shooters attack an office Christmas party in San Bernardino, killing and wounding dozens of people. FBI investigators descend on the scene, looking for clues about the identity of the killers. But as they try to find out who the active shooters are, they’re faced with a more urgent question…where are they and do they plan to strike again?