Procurator of King Přemysl II. Otakara Oldřich from Chlum and at the same time the administrator of Bezděz Castle has the authority to investigate and punish capital crimes in the region. This time he deals with the theft of the thorn from Christ's crown; a rare relic, which Havel from Lemberk has acquired and intends to dedicate to the Church of St. Welcome to Prague. The crime was committed just two days before the arrival of the king, who is to take part in the solemn consecration of the relic, so the whole affair threatens to be quite embarrassing. In a short time, other crimes pile up - the murders of the yeoman Jan from Strělče, the chaplain from Lember and the goldsmith Ruprecht from Jablonné. Are these crimes related or not? And what about the alleged rape of the goldsmith's wife? Are the Danish ambassador and the French noble involved in the crimes? Who and why kills Zdislava from Lemberk's beloved cats? Oldřich from Chlum is pressed for time to quickly solve all the crimes, but he traditionally does his job really well.