In 1984, Grace discovers the epsilon twistor, a device that could destroy a whole continent in a split second. Her calculations are like psychotic episodes and their dangerous consequences are inflamed by her mental instability and her left-wing politics. She initiates a project to develop the device in Japan, but is being pursued by Tony, a pathological killer working for MI5, a man who has hated Grace since their college days. The Epsilon Twistor is a spy thriller, with the fate of the Earth at stake. At a deeper level, it is a study of scientific creativity and psychosis.