The focus of the story is on a patient at a psychiatric clinic who kept a diary. Unexpectedly, the staff at the mental institution discover the girl's dead body, while her diary mysteriously disappears. Law enforcement immediately arrives at the crime scene. For police lieutenant Angel, this case becomes her first. She realizes that she will have to face numerous difficulties. Angel searches for the culprit among the staff and other patients. At times, she feels like she is on the brink of madness herself.