“You’re sure,” she murmured as Burroughs left them to interview the station clerk, “you’re sure they’ll never know?”

“I’m positive,” he stolidly responded.  “Just stick to your story.”

“The Evershams won’t question—­they are never interested in other people,” she mused, with thankfulness.  “But Mr. Falconer——­”

“Won’t have a doubt,” said Billy firmly.  His gloom closed in thickly about him.

* * * * *

It was a local, a train of corridor compartments.  In one, marked “Ladies Alone,” Arlee was ensconced, with an Englishwoman and her maid, and two pleasant German women, and in another Billy B. Hill sat opposite some young Copts and lighted pipe after pipe.  When the train started out on the High Bridge across the Nile to the eastern bank, he came out in the corridor to look out the wide glass windows there, and found Arlee beside him.

“How do you do?” she said brightly.  “How nice to meet accidentally like this—­you see, I’m rehearsing my story,” she added under her breath.

“Let’s see if you have it straight,” he told her.

“I arrive on a local which left Cairo this morning....  Did I come alone?”

“You’d better invent some nice traveling friend——­”

She shook her head in flat refusal.  “I won’t.  I’m not equal to inventing anything.  It’s bad enough now to—­to tell the necessary lies I have to.”  The brightness left her face looking suddenly wan and sorry.  “I suppose it’s part of my—­punishment—­for my dreadful folly,” she said in a low tone.

“It’s just part of the coin the world has to be paid in for its conventions,” Billy quickly retorted. “Don’t let it worry you like that—­in a day no one will think to question you.”

“I know—­but—­it’s having the memory always there.  Always knowing that there is something I can’t be honest about—­something secret and dreadful——­”

She was staring unseeingly out the window, her soft lips twitching.

“The Egyptians were a most sensible people,” said Billy.  “They drew up a list of commandments against the forty-two cardinal sins, and one of them was this, ‘Thou shalt not consume thy heart.’  That is a religious law against regret—­vain, unprofitable, morbid, devastating regret.  And you must take that law for your own.”

“Th—­thank you.”  The low voice was suspiciously wavery.  “I—­you see, I haven’t had time to think about it till just now—­we’ve been going so fast——­”

“And the best thing that could have happened.  And now that you have the time to think, you mustn’t think weakly.  It was just a nightmare.  And it’s over.”

“Just a nightmare....  And it’s over,” she repeated.  Her eyes lifted to Billy’s in a look of ineffable softness and wonder.  “It’s over—­because you came.”

“I want you to forget that.”  The young man spoke with cold curtness in his effort to combat the wild temptation of that moment.  “I only did what anyone else in my place would have done—­to have accomplished it is all the gratitude I want.  Please don’t speak of it to me again.  You must forget about it.”