What lurks behind the world of the living? What is it that hides just out of sight of human perception? There is more to our world than our eyes reveal. Mahito, a young high school girl, is about to find out. She has just died. Mahito lives at home with her father (an ex-pro wrestler) and her cousin Erika, who came to live with Mahito's family several years ago after the death of her parents. Erika is a shy and weak six year old, who has had difficulty adjusting to her new family - she needs constant looking after, and unfortunately, it is Mahito who ends up devoting most of her time to this task. So it was on a rainy night, when Mahito had gone out for groceries that she was struck by a car. Two days later she awakens at home, covered in dirt and blood, yet there is not a scratch to be found anywhere on her. Shortly thereafter she discovers that she had died that night of the accident, but a mysterious woman named Alice had arrived on the scene and brought her back to life. This strange woman shared a part of her "Sacred Heart" with Mahito, giving her life as a Median, or Undead. It is a strange world Mahito is introduced to. As a Median, she possesses unique powers and sees the world around her for what it really is - a place quite different than what we humans perceive. It is a darker more foreboding plane where danger can lurk behind any given corner.