A tragedy occurred in Class 3, Grade 2, No. 2 Middle School in City C - a teacher committed a knife attack, killing 5 students and seriously injuring 10 students. Doctor Xiao Zhihao and policeman Zheng Tingyi met in this case, and together they uncovered the secrets of the school and discovered secrets that had been sealed away ten years ago! A teenager committed suicide in the toilet, ghosts were counted on the stairs, and one strange thing after another happened one after another. How should they face it?
Concept: Weird, Suspense, Criminal Investigation, Reasoning
