Squire Ota is waiting in Písek for the arrival of the Czech king Přemysl II. Otakar, who is accompanied by Oldřich from Chlum. Because it is a hot summer, he goes to Otava to bathe, where he meets a naked girl who introduces herself to him as the wife of the powerful Bavor of Strakonice. However, he soon learns that the girl lied to him. He begins to search for her and thus becomes more and more entangled in the strange mystery of the lost jewels. Meanwhile, someone murders the country judge. And more murders follow. Fortunately, Oldřich from Chlum arrives in Písek with commander Diviš and together with Ota, they start searching. It soon becomes clear that uncovering the truth could be very dangerous, as the clues lead to the most important representatives of the royal court.