Near the courier station lies the Lohas Inn, a place that secretly gathers intelligence. The innkeeper, Tian Jinjin, is clever, alert, and kind-hearted; the waiter, Tian Dazhuang, is skilled in martial arts; the musician, Piao Daoyi, is knowledgeable and worldly; and the accountant, Madam Tian, has sharp eyes and an excellent memory. Each of the four harbors their own secrets, yet fate has brought them together. The high-spirited General Fu, demoted to the Central Post Station after offending a powerful noble, is in fact there to investigate a major case. Just as feelings begin to grow between him and Jinjin, an urgent border dispatch goes missing, and the courier is found murdered—plunging the entire city into turmoil.