Autumn 1942. Investigators from the military prosecutor's office Rokotov, Mirsky and Yelagin, who miraculously escaped from the Kyiv boiler, are arriving in Kharkiv, where the evacuation is already in full swing. They have important information about the activities of the German spy organization, which must be urgently transferred to the center. But an unexpected order from the leadership forces them to stay in Kharkiv. After all, together with the evacuated enterprises, under the guise of refugees, groups of German saboteurs are moving east, the purpose of which is sabotage and sabotage at military plants located in the Urals and Western Siberia. Trying to uncover channels for the spies to be sent to the Soviet rear, Rokotov of Yelagin learns that the organization operating in Kharkiv is directly linked to a Kyiv group they uncovered a few hours before the surrender of the city. And the curator of both of these groups holds a high position in the General Military Prosecutor's Office in Moscow.