Everything, though, depended on what the reconnaissance plane photographs might show.

Lockley did not see the plane nor consciously hear it.  There was the faintest of murmuring noises in the sky.  It moved swiftly toward the north, tending eastward.  The plane that made the noise was invisible.  It flew above the cloud cover which still blotted out nearly all the blue overhead.  It went on and on and presently died out beyond the mountains toward Boulder Lake.

Lockley tried to get Vale back, to tell him that radars had verified his report and that it would be acted on by the military.  But though he called and called, there was no answer.

An agonizingly long time later the faint and disregarded sound of the plane swept back across the heavens.  Lockley still did not notice it.  He was too busy with his attempts to reach Vale again, and with grisly imaginings of what might be done by aliens from another world when they found the workmen near the lake—­and Jill among them.  He pictured alien monsters committing atrocities in what they might consider scientific examination of terrestrial fauna.  But somehow even that was less horrible than the images that followed an assumption that the occupants of the spaceship might be men.

“Calling Vale ...  Vale, come in!” He fiercely repeated the call into the instrument’s microphone.  “Lockley calling Vale!  Come in, man!  Come in!”

He flipped the switch and listened.  And Vale’s voice came.

“I’m here.” The voice shook. “I’ve been trying to find where that exploring party went.”

Lockley threw the speech switch and said sharply, “The Army asked Survey if any of us had seen anything come down from the sky.  I gave Sattell your report to be forwarded.  It’s gone to the Pentagon now.  Two radars reported tracking the thing down to a landing near you.  Now listen!  You go to the construction camp.  Most likely they’ll get orders to clear out, by short wave.  But you go there!  Make sure Jill’s all right.  See her to safety.”

The switch once more.  Vale’s voice was desperate.

“A ... while ago a party of the creatures started away from the lake.  An exploring party, I think.  Once I saw a puff of steam as if they’d used a weapon.  I’m afraid they may find the construction camp, and Jill....”

Lockley ground his teeth.  Vale said unsteadily, “I ... can’t find where they went....  A little while ago their ship backed out into the lake and sank.  Deliberately!  I don’t know why.  But there’s a party of those ... creatures out exploring!  I don’t know what they’ll do....”

Lockley said savagely, “Get to the camp and look after Jill!  The workmen may have panicked.  The Army’ll know by this time what’s happened.  They’ll send copters to get you out.  They’ll send help of some sort, somehow.  But you look after Jill!”

Vale’s voice changed.

“Wait.  I heard something.  Wait!”