The story unfolds around a large settlement in the Nizhny Novgorod region, a closed administrative-territorial entity (ZATO), a city best known as Sarov.
For a long time, the settlement, which took its name from a swampy river, was associated with a site of Orthodox pilgrimage. One of the most important saints, Seraphim (meaning 'Flaming') of Sarov, lived and died there. The saint lived ascetically and was known for his unprecedented miracles. He hand-fed a bear, healed gravely ill people, and spent a thousand days and a thousand nights praying on a stone. It is believed that he predicted his death by stating that "his end will be revealed by fire." Later, in the Soviet era, the heroic figure of the wonderworker was replaced by the new protagonist, the nuclear physicist.