Supt. Kincaid of Scotland Yard investigates the death of a lady living in his building. Ill with cancer, she asked friends to help her commit suicide, but Kincaid suspects the morphine that killed her was administered by someone intent on murder, not euthanasia.

"Felix Pink is a retired widower leading a boring life and hoping to die a boring death. He volunteers as an Exiteer-someone who sits with terminally ill people as they die by suicide, assisting with logistics and lending moral support, then removing the evidence to take the burden off their loved ones. When Felix lets himself in to Number 3 Black Lane, he's there to perform an act of kindness and charity: to keep a dying man company as he takes his...