It´s Night ((kakao novel based on the korean drama "Night Has Come")

"It’s nighttime. Mafia, please raise your heads and confirm each other." After the midterm exams, during a sudden school trip, an enigmatic ‘Mafia Game’ app appears on everyone’s phones. Right in front of them, a classmate is brutally executed. In this unbelievable situation, before the shock can even subside, the midnight bell rings, and everyone falls into a deep sleep. In the mysterious game, which no one knows...