Alexei Korolev has nothing to complain about. He has his own room in an apartment shared with only one other tenant, a job in the police force that puts food on the table, and his good heatlh. In Moscow, in 1937, that's a lot more than most people have. But for the first time in a long time, Korolev is about to be truly happy: his son, Yuri, is coming to visit for an entire week. Shortly after Yuri's arrival, however, Korolev receives an urgent call from his boss. It seems an important man has been murdered, and Korolev is the only detective they're willing to assign to this sensitive case.