August, 1953. The Muscovite Maxim Smirnov, an assistant cameraman, travels to Semipalatinsk as part of a film crew with a secret mission. Here, in the open spaces of the Kazakh steppe, he encounters his first love, the young Dinara. The young people do not know that very soon they will be at the epicentre of events which will forever change not only their lives, but also those of mankind. Here, in Semipalatinsk, in this hot summer, the test of the first hydrogen bomb will take place...