As children, Han Yihang and his friend Xu Yining discover a notebook left behind by his father, filled with his lifetime of insights and unique methods of deduction. Years later, because of that notebook, Xu Yining returns to the city where she first met Han Yihang. As a murder case involving a schoolteacher is solved, an even greater mystery begins to unfold. Xu Yining is caught up in the whirlpool of a matricide case, while Han Yihang resumes his search for the truth behind his father's disappearance. Their paths twist and intersect like a spiderweb, and in the end, everything points to his father's notebook! Thanks to those notes, a thrilling murder game reaches its conclusion. Han Yihang, how will you break out of this predicament?