Karl Cohen, a chemist and mathematician who is part of The Manhattan Project, has discovered an alternate solution for creating the uranium isotope needed to cause a chain reaction: U-235. After convincing General Groves of his new method, Cohen and his team of scientists work at Oak Ridge preparing to have a nuclear bomb ready to drop by the summer of 1944 in an effort to stop the war on the western front What ensues is an altered account of World War II in this taut thriller.