The action takes place in 1773 on one of the islands of the Venetian lagoon, where the mystical Pearl Kingdom is located, ruled by the handsome Prince Pearl. The prince is an orphan; his mother, Queen Margaret, died when he was only two years old. A lonely, sad and depressed boy suffers from narcissism. He spends all his time at the old mirror, where he admires his reflection, wanting to merge with it and find happiness. The rest of the world does not exist for him. However, the prince leads another, secret life associated with the rising of the red moon over the Adriatic, which causes the ancient Greek island of Lesbos to emerge from oblivion, inhabited by beautiful nymphs who make the prince forget about his body and fill his soul with new feelings. On one of his last visits to the island, the prince meets the poetess Sappho, who quietly introduces him to adulthood and tells him that his island is full of mysteries that only the prince himself can solve. But for this he needs to go through the mirror he loves so much. The prince follows Sappho's advice, passes through the mirror and the terrible secrets of his kingdom are revealed to him, one after another, and each time he, a 21-year-old boy, has to make a choice between good and evil, proving his worth as a man and ruler. His will gradually strengthens, and the prince begins to learn to be an adult, understand people and let them into his heart.