Leningrad, spring 1942. After the first blockade winter, the conductor of the Bolshoi 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 - only a few musicians remained from the orchestra: someone died of hunger, someone went to the front, and someone went missing. But the concert should take place and thunder all over the world, so that both friends and enemies would hear: "Leningrad is alive!". Despite mutual distrust and complete rejection, the conductor and the lieutenant must accomplish the impossible: together to find the missing performers in the besieged city and provide the premiere of the Seventh Leningrad Symphony.