Building 41

She had once said that taking the codebook had been like tossing a stone into the ocean, the ripples of it had seemed endless. Now, some sixty years later, time finally catches up with Bletchley Park veteran Elsie Sidthorpe, as she is tested, once again, by Günther Möller, the renegade German with his own hidden past. But this time, Elsie has an insurance policy. Or two, in fact. When the first of them fails, Bletchley curator Harry Stammers is thrust into a desperate race to unravel her se...