Boston geneticist Dr. Saul Kramer is on the cutting edge of genetic disease research. Revered among clients at his IVF clinic, he harbors a dark secret. In addition to helping infertile couples conceive healthy babies, Dr. Kramer is obsessed, for his own dark reasons, with an alternate mission as well. In certain patients, he uses the gene editing technology CRISPR to tamper with embryos, not to improve the health of the embryos, but to replace a healthy gene with a deadly mutation. A young female journalist, Sammie Fuller, begins to suspect what he has done when three infants conceived at his clinic die mysteriously, all at about one year old. It's one thing to prove that Kramer has violated the Hippocratic oath in a such a heinous way, but quite another to convict him of murder in a court of law. What begins as a hunt for hard evidence ends with questions that much more difficult to answer.