The last days of 1933. After the failed attempt to assassinate King Alexander in Zagreb, it is clear that Yugoslavia is in a serious political crisis. Great political and strategic games are entangled both domestically and abroad, the very survival of Yugoslavia is called into question. However, Belgrade is shaken by something completely different; a gruesome murder on Avala, in the medieval fortress of Žrnov at the place where a monument to the unknown hero Ivan Meštrović will soon be built. Inspector Pletikosić, the current head of the Belgrade Department for Blood and Sexual Crimes, takes over the investigation, with the help of his young assistant Zečević.