An old aircraft designer dies at the hands of villains who entered the house in the middle of the night, and his granddaughter Kira manages to escape. The grandfather was the girl’s only close relative, and she is determined to find and punish his killers. Having discovered the first clue in her grandfather's secret archive, she herself tries to unravel the case. The thread stretches far into the past and leads to a mysterious person - the mysterious Richard Bertoni, who was called the “red Saint Germain”. Now, many years later, someone kills his best students - and the life of young Kira, persistently revealing old secrets, is also under threat... In each of Catherine’s novels, world secrets of the past unexpectedly appear in the present. The heroes of the books, for example, investigate the wreck of a liner, like the crash of the Titanic; receive strange letters with excerpts from Dyatlov’s diary while at a ski base in the mountains; they find the diary of the Kennedy assassin or learn interesting facts from the life of their ancestors, for example, that they knew the poet Nikolai Gumilyov. And all these secrets of the past turn out to be closely woven into the lives of the heroes and in one way or another influence their fate.