A story with a fascinating plot. An elderly man, a professor of philology, Nikolai Ivanovich Sosnovsky finds a stranger at his summer cottage. Upon closer examination, he recognizes him as his former classmate, whom he had not seen for many years and whose death he recently learned about. This is not the premise of a mystical thriller. More likely, a political militant. An aspiring killer shoots (in the literal sense of the word - he shoots poisoned arrows at his victims) former Soviet officers, participants in revolutionary liberation wars in Asia and Africa. And he is directed by a sinister and mysterious character nicknamed Koschey.