In the 22nd year of Daoguang's reign, Xining Prefecture received an edict: fifty taels of incense from Qinghai should be delivered to Tai Hospital within sixty days. Ma Jianshan is a perfumer. Three generations of our ancestors have been identifying scents for people at the Dangar Tea and Horse Market. With your eyes closed and you smell it, you can tell whether the bag of musk is Qilian Mountain horse musk deer or Sanjiangyuan forest musk deer, spring pouch or autumn pouch, how many years it has been sealed, and its grade. He has only dealt with noses all his life, not officials. But Master Daotai ordered him to be escorted. From Xining to Beijing, it is a journey of 3,400 miles, sixty days, and fifty taels of tribute. There was a heavy snowstorm in June in the Qilian Mountains. When I crossed the Lanzhou ferry, I was opened by someone. I found that an official had secretly changed the sachet under Xi'an City - the real incense had been repackaged, and the fake incense was left in the tribute box. There are people waiting for him to fail at every level. There are people hiding in every inn who want to see him lose his head. He only has one Qinghai mule, one green camp commander, and four soldiers. And a nose that can smell fakes from three inches away. A musk scent in the Forbidden City is not as good as the spring in Xining in June. A small person is pushed into the Qing Empire's relay machine - after sixty days, the person who comes back alive may not be the same person.