In the Han Dynasty, there was a poor scholar named Si-ma Mao who was knowledgeable but frustrated his whole life long. He did not want to conform to the distorted system that encouraged people to enter officialdom by paying their way.  Whenever he argued against it, he was brutally beaten.  Once, in a fury, he wrote down all his complaints. This enraged Yama, the ruler of the nether region, and so the poor scholar was taken to Hell to be tried.  In Hell, Si-ma Mao’s temper did not cool, and he continued to rebuke Yama harshly, even recommending himself to take on Yama’s position.  Amazed by his arrogance, the divine being ordered that he become Yama for half a day and so be in charge of the nether region for 12 hours.
Si-ma Mao, the “Yama for half-a-day,” finally fulfilled his ambition and began judging old cases of injustice.  He reviewed the cases of Xiang Yu, Han Xin, Queen Lu, and Yu Ji at the beginning of the Han Dynasty, intending to reward the good and punish the evil.  However, his interference resulted in entanglements among Guan Yu, Cao Cao, Lady Liu, Emperor Li Yu, Song Emperor Tai-zu, and Little Queen of Zhou for a thousand years of many generations.  Guided by Old Yama, Si-ma Mao got to see the fate of those who were judged by him when they were reincarnated, and realized that his intention of clarifying the entanglement actually made the situation even more twisted and distorted.  Si-ma Mao reached a deeper understanding about the way of Nature, but what should he do when he returned to Earth?