An experienced detective is investigating the murder of a woman, which at first seems like a typical crime. But at the crime scene, he finds a strange note: “You are not alone.” It unsettles him. As he dives deeper into the investigation, he starts to feel that he’s not just solving a case, but becoming part of a game where his reality is gradually being distorted. The further he goes, the more he feels that someone is watching him. And, even more strangely, that someone seems familiar.