Xu Xian, the crown prince's brother-in-law, has always roamed the streets acting like a reckless playboy. Unexpectedly embroiled in a murder case at the Music Bureau, he relied on his meticulous mind to unravel the intricate layers and crack the baffling mystery. Operating under an alias among the common folk, he laid down business routes using the dual-capital courier service and formed an alliance with a mysterious official using the alias "Zhao Guang." As hidden currents at court and sudden changes in the borderlands arrived one after another, the true grand vision hidden beneath his devil-may-care exterior is quietly unveiling a corner.