April 26, 1986, Ukrainian Soviet Socialist Republic. An early-morning explosion at the Chernobyl nuclear power plant sends workers scrambling to assess the damage. When reports reach the control room that the reactor's core is "gone," deputy chief engineer Anatoly Dyatlov, insisting that's impossible, sends men to the core itself to investigate. Meanwhile, Vasily, a fireman in the nearby town of Pripyat, is summoned to help put out the fire, leaving behind his wife Lyudmilla, who gathers with other residents of nearby Pripyat to marvel at the strange glow in the distance. As plant workers and firemen quickly succumb to radiation, Dyatlov and plant directors Viktor Bryukhanov and Nikolai Fomin meet with the Pripyat council and insist that radiation levels are not dangerously high; the council subsequently decides to seal off Pripyat and cut its phone lines to prevent the spread of "misinformation." As sick patients begin to stream into the local hospital, a skeptical academician, Valery Legasov, is tasked by the Central Committee of the USSR to serve as an expert on its Chernobyl task force.