"Please Remain Calm" is the second episode of the historical drama television miniseries Chernobyl, which details the nuclear disaster that occurred on April 26, 1986, and the consequences that everyone involved faced.

Inorganic chemist Valery Legasov and a Council of Ministers' deputy chairman Boris Shcherbina are sent to Chernobyl to investigate the incident where they discover that the situation is way worse what they expected, risking the live of millions including the citizens.

Mazin started to research for the project in 2014, reading several books and government reports that detail the events that happened during the explosion and its aftermath.

The episode received critical acclaim with praise towards the performances of Harris and Skarsgård, script, cinematography, direction, atmosphere, musical score, and the portrayal of the aftermath of the explosion.

After getting confirmation that nothing happened in the Ignalina nuclear plant, she fails to reach Chernobyl's staff leading her to realize that the source is coming from there.

In Chernobyl, the hospital has become overloaded with many citizens who are now suffering from acute radiation syndrome (ARS), including Vasily Ignatenko, Aleksandr Akimov, and Leonid Toptunov.

During the committee meeting, the members initially dismiss the severity of the explosion, believing that they are only dealing with a minor incident and considering that the radiation level is not dangerous at 3.6 roentgen.

Before the committee is dismissed, Legasov points out several mistakes in the report and suggests that the levels of radiation could be higher than expected if the core is exposed.

Dissatisfied that the city hasn't been evacuated yet, Legasov tells Shcherbina that despite their distance from the core, they are still absorbing radiation (though in their cases the symptoms will take longer to appear) and that they will likely be dead in five years.

[a] If the explosion were to occur, the blast would also destroy the three remaining reactors at Chernobyl, decimate the entire surrounding area, and spread high levels of radiation across all of Eastern Europe.

When Craig Mazin expressed interest on creating a show based on the Chernobyl disaster, he wanted to portray it as accurately as possible, leading him to read books and interview nuclear scientists.

[7] Skarsgard expresses: "Nobody would see it as a privilege to spend five months in a dilapidated nuclear plant, unless it was to play in a script like this by Craig Mazin, work with a director like Johan Renck, collaborate with a producer like Jane Featherstone, jam with an actor like Jared Harris and finally be at the feet of Emily Watson whom I have been missing for some 20 years.

The miniseries was a dramatic success of nuclear proportions, a grim story turned into a must-watch historical drama by a team of folks at the top of their game.

"[18] Euan Ferguson from The Guardian lauded the show for Harris's performance and its atmosphere, saying "[t]his enthralling, quietly spectacular, meticulously researched five-part series landed a mite irritatingly on Sky Atlantic, which many people don't have.

"[19] Pat Stacey from Irish Independent rated the show with 5 stars and stated "Writer Craig Mazin, best known before now for writing the comedy The Hangover and its sequels, and director Johan Renck have crafted an unflinching, devastatingly powerful drama with the tautness of a thriller and the chilling veracity of a documentary.

In fact, it is not hard to believe at this point that the total cultural impact of Chernobyl will be associated with that made in the Cold War era (when the world continuously faced nuclear holocaust) by the three-hour 1983 television film The Day After.

"[21] Alison de Souza from The Straits Times praised the episode for accurately recreating all the events that happened during the catastrophe, giving it 4 stars of 5.

Each nauseating moment, be it a shot of decaying human flesh or a decision made for the wrong reasons, has a purpose — and pays back the viewer for their investment.