Based on the novel of the same name by Aleksandr Lukin and Dmitriy Polyanovskiy. Russia, 1919. A young soldier of the First Cavalry Army, Aleksei Mikhalyov, is sent to work in the provincial Cheka. Here in the south of the country there is a large White Guard underground led by the elusive Markov. Aleksei gets into the gang, where he is mistaken for his own. The day of the operation to eliminate the white underground is appointed. But unforeseen circumstances destroy the plans of the Chekists.

Arriving on a resort muscovites - circus artist Gurov and professor Fedorov are forget the houses of passport. Girl-dispatch on mail, hurrying on an appointment, mixes up envelopes, that entails the row of the comic misunderstanding.