Major Clement Wisdom of SIS is sent to learn Morse Code and its Japanese equivalent, Kana Morse. But when a fellow student from the college is found dead and another missing, Clement begins to suspect espionage. While assisting the local police, Clement uncovers a network of enemy spies, fuelled by long held resentments and treacherous greed. In May 1942, three Japanese submarines entered Sydney Harbour.Their intention? To destroy the vast array of Allied ships in port. Or was there another reason...