Autumn of 1891. Before an overseas assignment to the East, Klim Ardashev arrives in Stavropol. There he learns that in the art gallery of a local merchant, there has been a swap of Leonardo da Vinci’s sketch “The Martyrdom of Saint Sebastian.” Not long afterward, a musician—the first violin of a theater orchestra—ends his life by suicide under very strange circumstances. Ardashev will have to investigate these incidents not only aboard a steamship traveling from Odessa to Alexandria, but also in the capital of Egypt.