Working as an Undercover Agent Next to Emperor Sui Yang

When Yang Yuan traveled to the Sui Dynasty, he met Tang Guogong Li Yuan by chance and was treated as a distinguished guest. When he was happy, he unexpectedly told his son Li Shimin that he was stunned and asked him to work as an undercover agent next to Emperor Yang of the Sui Dynasty... When Li Yuan heard this, he immediately clapped his hands and agreed. Yang Yuan was so panicked. What a shrewd and ruthless person Yang Guang, Emperor Yang of Sui Dynasty, was? Doesn't this require him to commit suicide? I suddenly felt that this kid Li Er was simply a more sinister character...