“Billy!” ejaculated the condemned man.

“Surest thing you know; but about the door?”

“Just a heavy bar on the outside,” replied Bridge.

“Easy,” commented Billy, relieved.  “Get ready to beat it when I open the door.  I got a pony south o’ town that’ll have to carry double for a little way tonight.”

“God bless you, Billy!” whispered Bridge, fervently.

“Lay low a few minutes,” said Billy, and moved away toward the rear of the guardhouse.

A few minutes later there broke upon the night air the dismal hoot of an owl.  At intervals of a few seconds it was repeated twice.  The sentry before the guardhouse shifted his position and looked about, then he settled back, transferring his weight to the other foot, and resumed his bovine meditations.

The man at the rear of the guardhouse moved silently along the side of the structure until he stood within a few feet of the unsuspecting sentinel, hidden from him by the corner of the building.  A heavy revolver dangled from his right hand.  He held it loosely by the barrel, and waited.

For five minutes the silence of the night was unbroken, then from the east came a single shot, followed immediately by a scattering fusillade and a chorus of hoarse cries.

Billy Byrne smiled.  The sentry resumed indications of quickness.  From the barracks beyond the guardhouse came sharp commands and the sounds of men running.  From the opposite end of the town the noise of battle welled up to ominous proportions.

Billy heard the soldiers stream from their quarters and a moment later saw them trot up the street at the double.  Everyone was moving toward the opposite end of the town except the lone sentinel before the guardhouse.  The moment seemed propitious for his attempt.

Billy peered around the corner of the guardhouse.  Conditions were just as he had pictured they would be.  The sentry stood gazing in the direction of the firing, his back toward the guardhouse door and Billy.

With a bound the American cleared the space between himself and the unsuspecting and unfortunate soldier.  The butt of the heavy revolver fell, almost noiselessly, upon the back of the sentry’s head, and the man sank to the ground without even a moan.

Turning to the door Billy knocked the bar from its place, the door swung in and Bridge slipped through to liberty.

“Quick!” said Billy.  “Follow me,” and turned at a rapid run toward the south edge of the town.  He made no effort now to conceal his movements.  Speed was the only essential, and the two covered the ground swiftly and openly without any attempt to take advantage of cover.

They reached Billy’s horse unnoticed, and a moment later were trotting toward the west to circle the town and regain the trail to the north and safety.

To the east they heard the diminishing rifle fire of the combatants as Pesita’s men fell steadily back before the defenders, and drew them away from Cuivaca in accordance with Billy’s plan.