The story follows Qin Su, an outstanding student who transmigrates to Anlu County in the Great Yong Dynasty and becomes a low-ranking night watchman. His father disappeared after taking his uncle's place in military service. Meanwhile, his relatives seize the family's property, and the Azure Stone Gang makes life difficult for him. Determined to learn martial arts but unable to afford the tuition, Qin Su is fortunate to receive an introduction from his fiancée, Wu Musi, and financial support from the Lin family, allowing him to begin his martial arts journey. After awakening a Diligence System, he accumulates talent through relentless day-and-night training, steadily improving his physique and comprehension. Despite having a lower-grade C aptitude, he overcomes the genius Zhang Xiaoyi, reaches the Ming Jin stage in just fifty days, punishes local bullies, and navigates the conflicts between powerful families and gangs. Later, he learns a secret inherited hard-body technique and becomes entangled in a series of mysterious cases. Through patience and perseverance, Qin Su breaks the limits of his natural aptitude, protects the woman he loves, clears up his family's troubles, and embarks on the path to advancement through the martial arts examinations.