Enigma

out of the way, the door opened and Puck appeared.
    'Sorry, Guy. Good morning, Thomas.' He gave them each a grim nod. 'There's been a development, Guy.'
    'Good news?'
    'Frankly, no, to be entirely honest. It is probably not good news. You had better come.'
    'Hell, hell muttered Logie. He gave Jericho a murderous look, grabbed his pipe and followed Puck out into the corridor.
    Jericho hesitated for a second, then set off after them, down the passage and into the Registration Room. He had never seen it so full. Lieutenant Cave was there, along, it seemed, with almost every cryptanalyst in the hut—Baxter, Atwood, Pinker, Kingcome, Proudfoot, de Brooke—as well as Kramer, like a matinee idol in his American naval uniform. He gave Jericho a friendly nod.
    Logie glanced around the room with surprise. 'Hail, hail, the gang's all here.' Nobody laughed. 'What's up, Puck? Holding a rally? Going on strike?'
    Puck inclined his head towards the three young Wrens who made up the Registration Room's day shift.
    'Ah yes,' said Logie, 'of course,' and he flashed his smoker's teeth at them in an ochre smile. 'Bit of business to attend to, girls. Hush hush. I wonder if you wouldn't mind leaving the gentlemen alone for a few minutes.'
    'I happened to show this to Lieutenant Cave,' said Puck, when the Wrens had gone. 'Traffic analysis.' He held aloft the familiar yellow log sheet, as if he were about to perform a conjuring trick. 'Two long signals intercepted in the last twelve hours coming out of the Nazis' new transmitter near Magdeburg. One just before midnight: one hundred and eight four-letter groups. One just after: two hundred and eleven groups. Rebroadcast twice, over both the Diana and Hubertus radio nets. Four-six-oh-one kilocycles. Twelve-nine-fifty.'
    'Oh, do get on with it,' said Atwood, under his breath.
    Puck affected not to hear. 'In the same period, the total number of Shark signals intercepted from the North Atlantic U-boats up to oh-nine-hundred this morning: five.'
    'Five?' repeated Logie. 'Are you sure, old love?' He took the log sheet and ran his finger down the neatly inked columns of entries.
    'What's the phrase?' said Puck. “'As quiet as the grave”?'
    'Our listening posts,' said Baxter, reading the log sheet over Logie's shoulder. 'There must be something wrong with them. They must have fallen asleep.'
    'I rang the intercept control room ten minutes ago. After I'd spoken to the lieutenant. They say there's no mistake.'
    An excited murmur of conversation broke out.
    'And what say you, O wise one?'
    It took Jericho a couple of seconds to realise that Atwood was talking to him. He shrugged. 'It's very few. Ominously few.'
    Puck said: 'Lieutenant Cave believes there's a pattern.'
    'We've been interrogating captured U-boat crew about tactics.' Lieutenant Cave leaned forwards and Jericho saw Pinker flinch at the sight of his scarred face. 'When Donitz sniffs a convoy, he draws his hearses up line abreast across the route he expects it to take. Twelve boats, say, maybe twenty miles apart. Possibly two lines, possibly three—nowadays he's got the hearses to put on a pretty big show. Our estimate, before the blackout, was forty-six operational in that sector of the North Atlantic alone.' He broke off, apologetically. 'Sorry,' he said, 'do stop me if I'm telling my grandmothers how to suck eggs.'
    'Our work's rather more—ah—theoretical,' said Logie. He looked around and several of the crypt-analysts nodded in agreement.
    'All right. There are basically two types of line. There's your picket line, which basically means the U-boats stay stationary on the surface waiting for the convoy to steam into them. And there's your patrol line, which involves the hearses sweeping forwards in formation to intercept it. Once the lines are established, there's one golden rule. Absolute radio silence until the convoy's sighted. My hunch is that that's what's happening now. The two long signals coming out of Magdeburg—those are most likely Berlin ordering the U-boats into line. And if the boats are now observing radio silence ...' Cave shrugged: he was sorry to have to state the obvious. 'That means they must be on battle stations.'
    Nobody said anything. The intellectual abstractions of cryptanalysis had taken solid form: two thousand German U-boat men, ten thousand Allied seamen and passengers, converging to do battle in the North Atlantic winter, a thousand miles from land. Pinker looked as if he might be sick. Suddenly the