The story is set in the winter of 1916. During the previous year, all the power of the German army was directed against Russia. After several crushing defeats, Russia lost about 2 million soldiers and many thousands of square kilometers of its territory. However, Germany failed in its main goal of 1915 - to force the Russian Empire out of the war. One of the most important episodes of the war in the East in 1915 was the German army's attempt to break through the Russian Northern Front, which ended in complete failure and with great losses because the German command was fed deceptive information. The author of this brilliant operation was General Vladimir Zhukovsky.
Realizing that Zhukovsky's talent may cause a lot of damage to Germany in the future, the German intelligence chief and his deputy order their best spy, Josef von Theofels (known as "Sepp"), to carry out the operation against the Russian general. The intention is to have Zhukovsky accused of taking bribes and to get him fired from his post as chief of Russian counterintelligence. Under the guise of the "Siberian industrialist" Emelyan Bazarov, Teofels penetrates into St. Petersburg. Using an acquaintance with Princess Vereiskaya, with whom Bazarov allegedly escaped from German captivity, he meets Zhukovsky, but the general's discernment and caution prevent the German spy from carrying out the intended provocation. Enraged, Theofels decides to make use of an unusual trump card in the fight against General Zhukovsky – the Wandering Man, or the Wanderer. This is a mysterious figure who is alternately considered a saint or a devil, who may be of use to Sepp in a new, cunning plan.