2017. The Soviet Union is preparing to celebrate the Centenary of the Revolution on a grand scale. The public sector of the economy is exceeding the plan, the private sector is raising the quality of goods and services to a level unattainable by Western competitors, space expeditions are exploring the Moon and storming Mars, and Soviet medicine and sports are fighting for the ideal health of citizens. Educational, scientific and cultural figures also make a significant contribution to the preparations for this significant date: films are made, exhibitions are held, collections are compiled about the achievements and exploits of the country over the entire hundred-year Soviet period. Historian Leonid Zimin discovers encrypted records in the archive about one of the key episodes of the Great Patriotic War. As he dives into the material, Zimin realizes that he is drawn into a strange game in which both ordinary citizens and government agencies, in particular the KGB, participate. All interested parties are waiting for Leonid to decipher the mysterious memoirs and are ready to force him to complete the work by any means. Zimin suddenly realizes that he is about to unwittingly rewrite the official history of the country, but it is too late to retreat. The historical version outlined in the memoirs suddenly finds confirmation in the present.