The book is an exciting detective story with elements of mysticism. The main heroes are young Soviet people of the 1970s, Muscovites. Many of them might never have met if an ancient secret hadn’t entered their lives— the casket of Marie de Medici and its seven mysterious “companions.” By force of circumstances, the miraculous relic ends up in a cramped room in a small Moscow lane. That is, in fact, where the chain of astonishing events begins—one of the links of which is the disappearance of a foreign tourist.