Chernobyl is a searing historical drama chronicling the world’s largest nuclear disaster at the Chernobyl power plant as well as the aftermath of its cleanup. The five-part miniseries also takes a deep dive into Soviet Russia in the late ‘80s, when KGB prowled the streets and blind party loyalty prevented high ranking officials from believing scientists and nuclear experts about the ramifications of radiation poisoning and nuclear fallout.

From first responders at the scene of the accident, to the bystanders unwittingly exposing themselves to the toxic release of airborne plutonium and graphite particles, tens of thousands of people lost their lives since that fateful night in April of 1986. Here’s everything we know so far about the compelling series.

IT’S A FIVE PART MINI-SERIES

Unlike Game of Thrones, Chernobyl is a gripping drama consisting of five parts. The mini-series approach allows HBO’s creative team and special effects crew to maximize the effect of recreating the greatest nuclear disaster the world has ever seen. Part of what makes the series so chilling is its relentless and frenetic pace, without a single wasted frame.

The taut episodes never let you take a breath, with the intensity mounting as the Chernobyl accident occurs and the aftermath is explored. With three episodes down and two to go, the historical drama is winding down to its epic conclusion. It airs Monday nights on HBO and its streaming services.

IT STARS TOP EUROPEAN TALENT

Chernobyl is a cooperative effort with Skydance (UK) and HBO (US), and as a result offers top tier talent from across the pond. Jared Harris plays chief accident investigator Valery Legasov, an expert on nuclear fission who must fight the stringent Soviet bureaucracy to mount the overwhelming cleanup efforts.

He’s aided by Stellan Skarsgard (Thor, The Hunt for Red October) as Boris Scherbina, a career party man who must choose between his political loyalties and his duty to the people of the SSR. Emily Watson plays nuclear expert Ulana Khomyuk who bravely tries to uncover the truth and give the victims a voice, despite being impeded at every turn.

IT’S BASED ON REAL EVENTS

The disaster at the Chernobyl power plant is the largest nuclear disaster in the world, which caused the deaths of tens of thousands by radiation poisoning, the ramifications of which are still being felt by citizens of the SSR. During a routine safety check in which the plant underwent a planned simulation of power failure, an inadvertent explosion occurred when the power regulating systems were shut off.

Reactor design flaws as well as reactor operators arranging the core contrary to a given checklist resulted in a malfunction and the core exploding. Hundreds of first responders and bystanders died from radiation poisoning within the first few hours and days, necessitating the SSR government to mount the largest cleanup of its kind in the world.

THE SOVIET GOV’T TRIED TO COVER IT UP

As Chernobyl shows, even the chief engineer at the power plant refused to believe the core exploded, despite being told otherwise by eyewitness accounts from his own staff. Rampant denial existed among several party officials in the SSR, who blamed a fire on the roof as the cause of plumes of fission waste flooding the air. Maintaining government and party stability was more important than revealing the truth.

Try as the SSR did to cover up the extent of the disaster, they couldn’t deny the effects of the radiation released into the atmosphere, and the facts that Soviet citizens were dying from radiation poisoning in droves. Children were told to stay inside in Germany because of the risk from the fallout.

THOUSANDS OF PEOPLE HAVE DIED SINCE THE INCIDENT

At the time of the incident, over a hundred people (including first responders such as firefighters and paramedics, bystanders, and engineers) died from radiation poisoning. The death toll kept climbing as the toxic plume of nuclear fission continuously rose from the area where the nuclear core exploded, blanketing the region in a dangerous haze of nuclear fallout particles.

In the weeks, months, and years that followed, it’s estimated almost 90,000 people in the Soviet Union died from symptoms relating to the event. Radiation poisoning affects your cells at the moment of cellular division, and begins to dismantle your DNA at a rapid pace, “melting” you from the inside out. Those that didn’t die immediately from exposure died from a version of cancer in the ensuing years.

THE GOV’T TRIED TO DOWNPLAY THE RADIATION LEVELS

To protect the Soviet Nuclear System, the SSR tried to downplay the effects of the radiation. At every turn, the government supported the findings of scientists that explained there was about as much danger from the fallout of the Chernobyl plant as from an X-Ray. Chief accident investigator Valery Legasov and other experts in nuclear fission proved otherwise.

The SSR manipulated its party members into believing that because “a thousand years of sacrifice” ran in their veins, they owed it to “The People” (an abstract concept as much as it represented the actual “public”) to keep the full ramifications of the radiation to themselves. The death toll soon spoke for itself despite their hubris.

PROBLEMS BEGAN WITH THE RESCUE EFFORTS

Halfway through Chernobyl, as the first responders desperately try to help the victims of the core explosion and fight the nuclear blazes, viewers can clearly see that the SSR wasn’t interested in the safety of its citizens. Not with the faulty safety tests it made engineers at the Chernobyl plant carry out, and not with the dispensary of proper safety equipment for the first responders.

We see firefighters fighting the blazes with no warning of the burn source, and without face masks. We see hospital staff without gloves. We see high ranking party officials denying statements from scientists about evacuation measures, until it’s already too late and the entire world knows how expandable the SSR viewed its people.

IT EXPOSES THE CLAUSTROPHOBIC WORLD OF THE USSR

In 1986, the Communist regime in the USSR was waning, but blind faith in the Soviet Union still existed among its high ranking party officials. Machinations made in the name of the “The People” benefited a select few while masquerading as what was best for the individual public. The KGB prowled the streets of every city, keeping tabs on every citizen. As the Soviet proverb goes, “Trust, but verify."

Ironically, in the case of the Chernobyl power plant incident, the USSR failed to even trust its scientists, and tried desperately to cover up the effects of the fallout. They were forced to mount the largest cleanup effort in history, which took years and hundreds of thousands of citizens to help complete.

THEY TOOK AGES TO EVACUATE, BUT NOT BEFORE THEY CUT OFF THE CITY

In response to the crisis, rather than allow for the immediate evacuation of the people of Chernobyl and surrounding towns, high ranking party officials decided it would be better to try to contain the incident and not start a widespread panic. How did they go about this? By cutting phone lines so that they could curtail the “spread of misinformation” (and incidentally so victims couldn’t contact their families and vice versa).

At the insistence of scientists and nuclear experts, they finally began an evacuation process when the threat of further explosions was imminent. By that point hundreds of people had already died from radiation fallout, and those that hadn’t were already infected.

THE ACCIDENT WAS ONLY THE BEGINNING

After the Chernobyl plant core exploded, rescue efforts were slow. Not only did the engineers not fully understand the ramifications of what had happened, they denied the dangers of the radiation fallout in chorus with the high-ranking party officials.

Because the chief engineer decided to keep filling the system tanks with water (despite there being no core anymore), when airdrops of sand and boron were used to put out the fire where the core used to be, the mixture covered reactor building 4, creating a ticking time bomb. The steam from the hot water and plutonium particles would cause an explosion ten times greater than the original unless miners tunneled beneath it and drained the water.