Roxie Maeda is a college senior who hears voices in her head. When she first sees the demonic creature haunting her crush, she blows it off as a hallucination, but then it shows up in her Psych class, visible to everyone.
Its appearance triggers a police search of the campus, which reveals a bag of guns right outside the classroom. Someone was planning to shoot up the school. Over time, the creature discloses that he is a pain eater—a cursed, undead human who eats pain demons that arise from injuries, taking the pain into himself.
His selflessness sways her, and she befriends him only to fall in love. Together, they resolve to break his curse and save Prometheus University from its unknown attacker.