Under a professional exchange program, Sergeant John McKenzie arrives in Russia from the United States. The American not only becomes a partner of the investigator Vasilisa Vikhreva, but also temporarily settles in her apartment. It is hard for John and Vasilisa to work together - their differences in personalities and mentalities affect their relations. But the successful results of their joint investigations convince their superiors to create a special department to combat crimes committed by foreigners and against foreigners in Russia and put them in charge. Unraveling one case after another, the partners find themselves embroiled in an international spy game around a major scientific discovery.