This book is based on a short story written several years ago. The main character of the book, Vsevolod, lived a measured life until one meeting with an extraordinary and mysterious girl intervened in its course. Every day he became more and more interested in Katya, she fascinated him with her spontaneity and depth of views on many things, Vsevolod felt some kind of inexpressible connection between them. But the strange and sudden disappearance of Katya right before his eyes left only questions... Over the next few years, he tried to understand what had happened, radically changing his life, and soon began to receive answers that drew him into the world of incomprehensible secrets, which he was ready to share with the man. secret knowledge.