The series follows the tragedy that occurred when terrorists attacked at the annual Boston Marathon on April 15, 2013. They carried out the attack by placing two homemade pressure cooker bombs which detonated near the finish line of the race 14 seconds and 210 yards (190 m) apart. That resulted in three fatalities and hundreds injured, including 17 who lost limbs. With the help of archive footage, interviews with investigators, witnesses, survivors, and occasional reenactments, it offers details about the FBI investigation into what was quickly deemed a domestic terrorist attack.
In the first episode, hours after the blasts, investigators pore over evidence. One photo and a few seconds of footage lead to a breakthrough - and an agonizing choice.

The message of the group begins to change and losing identity and group mentality is pushed. With more lockdowns and rules, longtime members of the group begin to question or leave. With no sex permitted with members, Dick Joslyn’s membership in the cult poses problem for Do... leading to a new request for the group.
With dwindling numbers, the group needs a new boost of membership. The Exit begins to be discussed as the Hale-Bopp Comet approaches.

This is the story of two of the biggest scientific breakthroughs of the 21st century, told by the incredible scientists who made them happen. The first is LIGO’s measurement of gravitational waves coming from a black hole merger, and the second, the Event Horizon Telescope’s image of a black hole.

By August 1949 the USSR became the world's second superpower, thanks to its spies who had stolen America's atomic secrets. But by March 1953, Stalin is dead and KGB chief, Beria, is executed later the same year. Nikita Kruschev tries to reduce the power of the security service, splitting it into several sections...but it doesn't last and, soon, the KGB is back.
In the USSR, countless KGB operatives spied on opponents of the regime at home, guarded the state and party leadership, and abroad tried to find out as much as possible about the intentions of the NATO countries and, if possible, to sabotage them.

In 2011, a Social Security lawyer named Eric C. Conn and a judge named David Daugherty were investigated for committing massive fraud over many years. Conn figured out that he would get paid a hefty retainer for every Social Security disability payment he managed to get approved, so he and Daugherty (who need quick cash to pay for his daughter’s upcoming narcotics trial – which presumably meant bribing an awful lot of people) came to an arrangement.
In the second episode, Investigators starts to collect evidence against Eric and Judge Daugherty. The whistle-blowers are pressured.

A look into how the body defends itself against all odds through the stories of a nature survivalist, rancher twins, a doctor who survived Ebola and a cancer therapy recipient. The Immune System, essential to our survival every second, is the most complex and least understood piece of our biology.