“From Germany it could be reached, but it was Swiss territory.  At any rate I think I am the only civilian who has been there, and who has viewed from there this enormous work in which the Huns are engaged.

“And I belive that this mysterious, overwhelmingly enormous work is nothing less than the piercing—­not of a mountain or a group of mountains—­but of that entire part of Switzerland which lies between Germany and France.

“I believe that a vast military road, deep, deep, under the earth, is being carried by an enormous tunnel from far back on the German side of the frontier, under Mount Terrible, under all the mountains, hills, valleys, forests, rivers—­under Switzerland, in fact—­into French territory.

“I believe it has been building since 1871.  I believe it is nearly finished, and that it will, on French territory, give egress to a Hun army debouching from Alsace, under Switzerland, into France behind the French lines.  That part of the Franco-Swiss frontier is unguarded, unfortified, uninhabited.  From there a Hun army can strike the French trenches from the rear—­strike Toul, Nancy, Belfort, Verdun—­why, the road is open to Paris that way—­open to Calais, to England!”

“This is frightful!” cried the girl.  “If such a dreadful—­”

“Wait!  I told you that it is merely a surmise.  I don’t know.  I guess.  Why I guess it I have told you....  They were savage with me—­those Huns....  They got nothing out of me.  I lied steadily, even when drunk.  No, they got nothing out of me.  I denied I had seen anything.  I denied—­and truly enough—­that anybody had accompanied me.  No, they wrenched nothing out of me—­not by starving me, not by water torture, not by their firing-squads, not by blows, not even by making of me the drunkard I am.”

The pencil fell from Miss Erith’s hand and the hand caught McKay’s, held it, crushed it.

“You’re only a boy,” she murmured.  “I’m not much more than a girl.  We’ve both got years ahead of us—­the best of our lives.”

“You have.”

“You also!  Oh, don’t, don’t look at me that way.  I’ll help you.  We’ve got work to do, you and I. Don’t you see?  Don’t you understand?  Work to do for our Government!  Work to do for America!”

“It’s too late for me to—­”

“No.  You’ve got to live.  You’ve got to find yourself again.  This depends on you.  Don’t you see it does?  Don’t you see that you have got to go back there and prove what you merely suspect?”

“I simply can’t.”

“You shall!  I’ll make this right with you!  I’ll stick to you!  I’ll fight to give you back your will-power—­your mind.  We’ll do this together, for our country.  I’ll give up everything else to make this fight.”

He began to tremble.

“I—­if I could—­”

“I tell you that you shall!  We must do our bit, you and I!”

“You don’t know—­you don’t know!” he cried in a bitter voice, then fell trembling again with the sweat of agony on his face.