As he paused, evidently hoping for a suggestion from Gale, the silence was broken by the clear, ringing peal of a bugle.  Thorne gave a violent start.  Then he bent over, listening.  The beautiful notes of the bugle floated out of the darkness, clearer, sharper, faster.

“It’s a call, Dick!  It’s a call!” he cried.

Gale had no answer to make.  Mercedes stood as if stricken.  The bugle call ended.  From a distance another faintly pealed.  There were other sounds too remote to recognize.  Then scattering shots rattled out.

“Dick, the rebels are fighting somebody,” burst out Thorne, excitedly.  “The little federal garrison still holds its stand.  Perhaps it is attacked again.  Anyway, there’s something doing over the line.  Maybe the crazy Greasers are firing on our camp.  We’ve feared it—­in the dark....And here I am, away without leave—­practically a deserter!”

“Go back!  Go back, before you’re too late!” cried Mercedes.

“Better make tracks, Thorne,” added Gale.  “It can’t help our predicament for you to be arrested.  I’ll take care of Mercedes.”

“No, no, no,” replied Thorne.  “I can get away—­avoid arrest.”

“That’d be all right for the immediate present.  But it’s not best for the future.  George, a deserter is a deserter!...Better hurry.  Leave the girl to me till tomorrow.”

Mercedes embraced her lover, begged him to go.  Thorne wavered.

“Dick, I’m up against it,” he said.  “You’re right.  If only I can get back in time.  But, oh, I hate to leave her!  Old fellow, you’ve saved her!  I already owe you everlasting gratitude.  Keep out of Casita, Dick.  The U.S. side might be safe, but I’m afraid to trust it at night.  Go out in the desert, up in the mountains, in some safe place.  Then come to me in camp.  We’ll plan.  I’ll have to confide in Colonel Weede.  Maybe he’ll help us.  Hide her from the rebels—­that’s all.”

He wrung Dick’s hand, clasped Mercedes tightly in his arms, kissed her, and murmured low over her, then released her to rush off into the darkness.  He disappeared in the gloom.  The sound of his dull footfalls gradually died away.

For a moment the desert silence oppressed Gale.  He was unaccustomed to such strange stillness.  There was a low stir of sand, a rustle of stiff leaves in the wind.  How white the stars burned!  Then a coyote barked, to be bayed by a dog.  Gale realized that he was between the edge of an unknown desert and the edge of a hostile town.  He had to choose the desert, because, though he had no doubt that in Casita there were many Americans who might befriend him, he could not chance the risks of seeking them at night.