People are voluntarily dying before their time in California. Some call it assisted suicide when cancer or heart disease or painful old age make the quality of life unbearable. Others say it is murder, that no-one has the right to help others take their own life.

As the debate rages over whether euthanasia should be legalised or not the man at the centre of the row, nick-named Doctor Death, continues his work. Dr Alex Delaware joins in the argument, but when Detective Milo Sturgis comes to him with the suspicion that some of Doctor Death's patients are not willing collaborators, Delaware finds himself on the front line of the affair, and increasingly believes that euthanasia is not the prime motivation. So what is driving Doctor Death to kill so many?