When a person dies, their soul leaves the body in the form of a butterfly and the body itself rots away quickly after.<br /> <br /> Ono lost his entire family in a plane crash fourteen years ago. But since this tragedy, the body of Senri, his twin sister, is still intact while the butterfly that contains his soul was stolen by a mysterious individual during the accident, leaving her unconscious and in a vegetative state.<br /> <br /> In order to get back his sister's butterfly, Ono joins the famous "Death Bureau", a state agency specialized in the capture, conservation and managment of the butterflies before they dissapear for good 49 days after the death of the host. <br /> <br /> Using the butterflies, the family of the deceased can come in contact with their loved ones in the form of a 3D hologram.