Leng Qiu receives a secret mission to pretend to be a student at Yongming National University. His mission is to protect a girl named Wang Yuting. As a soldier who only knows how to slaughter demons, he is not good at words. To complete his task, Leng Qiu protects her in secret. Until one day, a demon suddenly bursts into the school. Leng Qiu realizes that there is a dark force at work. Nevertheless, he's prepared to face all challenges without fear of defeat because he's the best demon slayer ever.