When a writer known as a humorist quotes Mary Shelley in an epigraph to a serious novel, it is difficult to know how to interpret it. “The opinions which naturally spring from the character and the situation of the hero are by no means conceived as existing always in my own conviction; nor is any inference justly to be drawn from the following pages as prejudicing any philosophical doctrine of whatever kind.” Mary Shelley’s Frankenstein, the first genuine science fiction novel, is most often read as a warning against the character of Dr. Frankenstein, the scientist who wants to play God by creating human life out of body parts. Anyone who has read the novel—and not just pop culture’s appropriation of it—knows that it is difficult to take Shelley seriously when she claims not to advance any philosophical view.

Whether intended ironically or not, Kevin Guilfoile’s use of this quote to introduce his engaging futuristic thriller Cast of Shadows makes sense. The novel is above all a great page-turner, and it is not easy to discern where he stands on some of the difficult ethical questions. The plot revolves around a human cloning specialist, Dr. Davis Moore, whose 16-year-old daughter was raped and murdered. The crime was never solved, prompting Moore to secretly clone the killer so that he could look into his eyes, and maybe use the image to find him. This is not typical speculative fiction about cloning, which tends to be dystopic and otherworldly. Instead, Guilfoile has created an eerily plausible future world that differs from ours in only two significant ways: human cloning is legal and practiced regularly as a way to help infertile and genetically at-risk parents to have children; and a virtual reality computer game called “Shadow World” has most Americans addicted to going on-line to create, and play out, other lives for themselves. The novel’s title suggests the game’s symbolic significance: fiction is a kind of Shadow World that enables the writer to alter our familiar landscape just slightly to see what will happen.

But whereas you might expect this novel to employ its “cast of shadows” to deliver some kind of judgment on cloning, it does not. Instead it assumes, rather realistically, that the political battle over biotech is likely to be won by extremist scientists who, like Dr. Moore, acknowledge that they are playing God, but feel justified because they are “doing good” with this power. It also assumes that extremists on the opposing side will always be religious zealots on the order of abortion clinic bombers. Neither side smells of roses here.

So instead of focusing on the ethics of cloning, the novel focuses on the aftermath of Moore’s particular decision. This move ensures that the drama of the novel comes not from dry speeches about ethics or useless arguments about whether or not clones have souls, but from the playing out of the “nature vs. nurture” debate. Will the clone of a killer necessarily become a killer himself, or will he make different choices? And even more significantly, how will the knowledge of being the clone of a killer affect these choices? But here we must remember that this redirection of our attention to the whole idea of human choice is itself a moral move. For although Guilfoile does not take a stand on the cloning issue, he also never doubts that Moore’s decision to clone the killer was wrong—a decision that someone who is used to playing God will find a little too easy to make. Dr. Moore resembles Dr. Frankenstein in that the problem is not the technology but his particular attitude toward using it. Indeed, the moment of Moore’s choice to clone a killer is chilling precisely because, like Dr. Frankenstein, he gives so little thought to morality or even to the pragmatics of the future world he is about to create.

Ultimately Guilfoile illustrates how cloning is just one more new technology that opens up rather old questions in ethics that center around the nature of being human. And it seems to answer in the best narrative style by emphasizing that it is our power to choose that defines us. No matter how much our genes determine us, on the human stage, it is our choices that turn a cast of shadows into a cast of flesh and blood—and it is there that either the beauty or the horror lies.