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 - the difference in characters and mentalities affects. But the successful results of joint investigations convince the leadership to create a special department around them to combat crimes committed by and against foreigners in Russia. Unraveling one case after another, the partners find themselves embroiled in an international spy game around a major scientific discovery.