In the coronary care unit at one of Copenhagen's leading medical centres, a nurse fills a syringe with an overdose of heart medication and stealthily enters the room of an older male patient. Six days earlier, a paperboy on his route in the centre of the city stumbles upon a macabre find: the body of a dead woman, lying in a fountain, her arms marked with small incisions. Cause of death? Exsanguination - the draining of all the blood in her body. Clearly, this is no ordinary murder. Jeppe Korner, recovering from a painful divorce and in the throes of a new relationship, takes on the investigation. His partner, Anette Werner, now on leave after an unexpected pregnancy, is restless at home. While Jeppe leads the official search, Anette can't stop herself from doing a little detective work as well. But operating on her own exposes her to dangers she can't even begin to realise. As the investigation ventures into dark and dangerous corners, it uncovers an ambition and greed festering beneath the surface of caregiving institutions, all leading back to the mysterious Butterfly House.
