Strange and, at first glance, unrelated murders are occurring in the capital city. The respectable jeweler Kovalevsky dies, someone tries to kill his mistress Valeria, a treasure hunter disappears without a trace... During the investigation, it turns out that all the victims are somehow involved in the mystery of the ancient “Scarlet Drop” rubies, given by the Indian Raja to his beloved Sabhidari and disappeared from her death in the darkness of millennia.