In May 1944, RCMP Mountie Miles Lundin is assigned temporarily to England to be indoctrinated into the most imporant secret of the war - the ULTRA intercepts. Instead, he is called on to solve a murder of a Canadian soldier just before the amphibious invasion of France - code named NEPTUNE. As he works through the list of possible motives and suspects, he uncovers tensions between Canadian forces and British Comnandos that trace back to the calamitous raid at DIeppe in 1942. He also has to manage a conflict between the Canadian force leadership and his friend and colleague in the British Admiralty, Commander Ian Fleming.