Light divides the Universe into two: Day and Night. Good and Evil. Life and Death. Now its power, harnessed by a new generation of optical computers, attempts to answer mankind's last great question: What happens to us when we die? But this is perilous knowledge, as Dr. Miles Fleming, a brilliant young neuroscientist, discovers. To find the truth he must challenge the certainties of both science and religion, and embark on a journey which jeopardises his most basic assumptions and beliefs. On reaching the final terrifying revelation he realises that there are perhaps some things mankind should never know. For shining a light on the truth can sometimes reveal the darkest recesses of hell itself.