This is a story that took place in the last year of the life of the prime minister of the Tang Dynasty, the detective Di Renjie. During this year, he has to face: intertwined and unimaginably suspenseful cases; magnificent and ups and downs of border wars; treacherous Changeable, intriguing political conspiracies, as well as his own lingering, depressing emotional past... Let's see how Di Renjie breaks through the fog in this series of nine-nine-nine puzzles!