On her seventieth birthday, Li Shuying voluntarily signs up to protect her granddaughter, who is about to be chosen by the "Horror Game," entering one perilous rule-based instance after another. While others fear the supernatural, she relies on seventy years of life experience, courage, and wisdom in dealing with people to seek the truth, unite companions, and change tragedies across worlds such as manors, mad towns, dynasties, and academies. After achieving perfect clears time and again, she discovers that monsters are not necessarily evil, and that what is truly terrifying is often the control and oppression hidden behind the rules. Alongside system assistant 999, she will gradually begin to shake the very foundations of the Horror Game itself.