1912. The First World War is not far off. Young aviators Vladimir Slyusarenko and Lidiya Zvereva, the first Russian woman aviatrix, are working on a project for a reconnaissance airplane. Their activities are overseen by the Russian military department. For work on the aircraft, Riga is chosen—with its factories where orders for engines and equipment can be placed, and with its airfield located on the territory of the hippodrome in Solityud.
At the same time, Maximilian Ronge, one of the leaders of the intelligence service of Austro-Hungary—which has its own spy network in Russia—sends three agents to Riga: Tulpan, Centaur, and Aldu. Their task is, at best, to recruit the young aviators, and at worst—to simply steal the drawings…