The film tells about the shooting of a demonstration of workers in Novocherkassk in 1962. Lyudmila is a party worker of the local city committee, a staunch communist. During a workers' strike at the Novocherkassk Electric Locomotive Plant, Lyudmila witnesses the shooting of a workers' demonstration by order of the Government Commission, which is trying to hide the fact of a mass strike in the USSR. During the execution, Lyudmila's daughter disappears in the square, which makes a change in Lyudmila's worldview. Despite the blockade of the city, mass arrests and attempts by the Soviet authorities to hide what happened, she is looking for her daughter everywhere.