The Third Prince

King Zeme and his queen despaired about having offspring after their firstborn went missing, until a weird gypsy ritual and prediction apparently worked, yielding them twin sons Jaromir and Jaroslav, who grow unnaturally fast and inseparable, like their matching horses, dogs and magical swords. A mysterious, spelled painting hidden in the palace, also with a double, gets them obsessed with the depicted princess Milena, whom one sets out to find in the enchanted Diamond Mountain realm, where priceless gems are mined in great quantities, only to be kept there bewitched by her and her secret twin sister. Their remaining brother rides out to find them and accepts the triple challenge to free the twins by performing three daunting tasks.