Leningrad, spring 1942. After the first winter of the siege, the conductor of the Grand Symphony Orchestra of the Radio Committee receives an important government task — to perform Shostakovich's Symphony No. 7 in the besieged city. It seems impossible — there are only a few musicians left of the orchestra: someone died of hunger, someone went to the front, and someone went missing. But the concert must take place and thunder all over the world, so that both friends and enemies can hear: "Leningrad is alive!" NKVD officer Anatoly Seregin was seconded to help the orchestra's leader Karl Eliasberg.