“No!  I won’t!” Ed declared.  “I don’t want to see the Rio Grande to-night.  I won’t be involved—­”

“But you are already involved.  Come!  There is no time to waste, and I have something to say to you.  You will drive me to the river, and my horse will remain here until I return for him.”

There was no mistaking the command in Longorio’s tone; the master of Las Palmas rose as if under compulsion.  He took his hat, and the two men left the room.

“Oh, my God!” Paloma gasped.  “They’ll be in time, and so will the Lewis gang.”

“Quick!  Ed will take his runabout—­we’ll follow in my car.”  Alaire fled to make herself ready.  A few moments later she looked out from her window and saw the headlights of Ed’s runabout flash down the driveway to the road; then she and Paloma rushed to the garage where the touring-car stood.

“They’ll never expect us to follow them”—­Alaire tried to speak hopefully—­“and we’ll drive without lights.  Maybe we’ll get there in time, after all.”  As the machine rolled out through the gate she elaborated the half-formed plan that had come to her:  “The brush is thick along the river; we can leave the car hidden and steal up to the pump-house.  When we hear the boat coming maybe we can call out in time to warn your father.”

“The moon is rising,” Paloma half sobbed.  “They’ll be sure to see us.  Do you think we’re ahead of Tad Lewis?”

“Oh yes.  He hasn’t had time to get here yet, but—­he’ll come fast when he starts.  This is the only plan I can think of.”

Alaire drove as swiftly as she dared, following the blurred streak of gray that was the road, and taking the bumps with utter recklessness.  Already the yellow rim of the moon was peering over the horizon to her right, and by its light she found the road that turned abruptly toward the Rio Grande, a mile or more distant.  The black mud from the last heavy rain had hardened; the ruts in this side road were deep, and the car leaped and plunged, flinging its occupants from side to side.  Ahead loomed the dark ridge of the river thickets, a dense rampart of mesquite, ebony, and coma, with here and there a taller alamo or hackberry thrusting itself skyward.  But even before they were sheltered from the moonlight Paloma saw the lights of another automobile approaching along the main-traveled highway behind them—­the lights, evidently, of Tad Lewis’s machine.  A moment later Alaire’s car drove into the black shadows, but, fearing to switch on her headlights, she felt her way cautiously between the walls of foliage until at her right another opening showed, like a narrow arroyo, diverging from the one they followed.  Into this she swerved, regardless of the fact that it was half grown up with brush.  Thorny branches swept the sides of the machine; rank, dew-soaked grass rose to the height of the tonneau.  The car came to a jolting pause, then the motor ceased its purring, and the two women sat motionless, listening for the rattle of the on-coming machine.  It had been a short, swift, exciting ride.  “Young Ed’s” runabout could not be many minutes ahead of them.