Sir Walter flung himself wearily into an arm-chair.  ’I wish I could be an optimist,’ he said, ’but it looks as if we must own defeat.  I’ve been at this work for twenty years, and, though I’ve been often beaten, I’ve always held certain cards in the game.  Now I’m hanged if I’ve any.  It looks like a knock-out, Hannay.  It’s no good deluding ourselves.  We’re men enough to look facts in the face and tell ourselves the truth.  I don’t see any ray of light in the business.  We’ve missed our shot by a hairsbreadth and that’s the same as missing by miles.’

I remember he looked at Mary as if for confirmation, but she did not smile or nod.  Her face was very grave and her eyes looked steadily at him.  Then they moved and met mine, and they seemed to give me my marching orders.

‘Sir Walter,’ I said, ’three years ago you and I sat in this very room.  We thought we were done to the world, as we think now.  We had just that one miserable little clue to hang on to—­a dozen words scribbled in a notebook by a dead man.  You thought I was mad when I asked for Scudder’s book, but we put our backs into the job and in twenty-four hours we had won out.  Remember that then we were fighting against time.  Now we have a reasonable amount of leisure.  Then we had nothing but a sentence of gibberish.  Now we have a great body of knowledge, for Blenkiron has been brooding over Ivery like an old hen, and he knows his ways of working and his breed of confederate.  You’ve got something to work on now.  Do you mean to tell me that, when the stakes are so big, you’re going to chuck in your hand?’

Macgillivray raised his head.  ’We know a good deal about Ivery, but Ivery’s dead.  We know nothing of the man who was gloriously resurrected this evening in Normandy.’

’Oh, yes we do.  There are many faces to the man, but only one mind, and you know plenty about that mind.’

‘I wonder,’ said Sir Walter.  ’How can you know a mind which has no characteristics except that it is wholly and supremely competent?  Mere mental powers won’t give us a clue.  We want to know the character which is behind all the personalities.  Above all we want to know its foibles.  If we had only a hint of some weakness we might make a plan.’

‘Well, let’s set down all we know,’ I cried, for the more I argued the keener I grew.  I told them in some detail the story of the night in the Coolin and what I had heard there.

’There’s the two names Chelius and Bommaerts.  The man spoke them in the same breath as Effenbein, so they must be associated with Ivery’s gang.  You’ve got to get the whole Secret Service of the Allies busy to fit a meaning to these two words.  Surely to goodness you’ll find something!  Remember those names don’t belong to the Ivery part, but to the big game behind all the different disguises . . .  Then there’s the talk about the Wild Birds and the Cage Birds.  I haven’t a guess at what it means.  But it refers to some infernal gang, and among your piles of records there must be some clue.  You set the intelligence of two hemispheres busy on the job.  You’ve got all the machinery, and it’s my experience that if even one solitary man keeps chewing on at a problem he discovers something.’