Dr. Rudolf von Hacklheber can’t see Bletchley Park, because it is the second best kept secret in the world, after Ultra Mega. But from his office in Berlin, sifting through dispatches from the Beobachtung Dienst, he can glimpse fragments of those trajectories, and dream up hypotheses to explain why they are just so. If the only logical hypothesis is that the Allies have broken Enigma, then Detachment 2702 will have failed.