Accidentally passed through a book and became an undercover agent, lurking in the palace of Prince Sheng of the Northern Kingdom to obtain information. In order to fulfill the orders of the fifth prince of the Eastern Kingdom, he approached Prince Sheng step by step. When Prince Sheng gradually relaxed his guard against him, he asked to write a family letter to express his homesickness. It read
Everything is fine with the child. Don't worry about it, parents. In the early spring of next year, we will take you and your elders to the capital to enjoy themselves.
On the surface everything was normal, but at the end of the letter it was written in special ink
A plague breaks out in the Northern Kingdom, and troops are dispatched immediately...
Intention: You probably understand what harm is, and you can't go too far as a human being.