On the day after the college entrance examination, Jiang Zhiwei opened his eyes and was tied to a raft on the river. The flood peak is approaching in the upper reaches, and people all over the city are still kneeling on the shore to pray to the river god. She relied on cloud colors, water marks and a basic arithmetic problem to save a whole city of people before the embankment collapsed. But when the flood receded, the relief granary was empty, and his father, who had been missing for seven years, was also waiting to be executed on death row. Some people use the lives of disaster victims to fill their accounts, while others want those who know the truth to shut up forever. Jiang Zhiwei held on to the pen that was almost out of ink, and walked into the old cases step by step, from food inspection and epidemic control to river repair and girls' school. She will make miscalculations, get hurt, and be cornered by power. If this world was really a test paper, she would write back the answers for everyone who was left out.