Lee So Ri is a college student who dreams of becoming a detective while living a simple life with her grandmother. But everything suddenly changes when a terrifying incident happens inside their classroom. One of her classmates vomits blood, strange creatures begin appearing around the school, and a mysterious smell of blood spreads everywhere. Trapped in the middle of chaos, So Ri discovers a hidden world filled with monsters, secrets, and danger. Soon, she meets a mysterious organization called Task Force Alawain that knows more about her than she realizes. As dark truths slowly unfold, So Ri's life becomes connected to a terrifying mystery that could change everything she knows about the world and herself.