The checklist did not have a page for this.

Twenty minutes into the second walk, Armstrong called in a shape on the crater rim, north and upslope. He described it the way he would have described a rock. Size, distance, bearing. Then he said it was standing.

It came down the slope while they watched. It walked. It took the grade at an angle, the way a man does on a hillside, and it was not wearing a suit.

He stopped a few feet short of them, said hello, and used their names. Not their callsigns. Their names.

Then he spoke, and he spoke like nothing either of them had ever heard, and neither of them interrupted him.

“I was sent by the Source of all humanity, to make sure you could flourish and to keep the darkness at bay. For countless millennia I have been here. In the beginning there were many that contested, and I slew them all, but after a time it grew quiet, so I watched.

Now I sit and watch. That is how I know your Eric and Mark sit and wait for your return. They are good boys, just as you two will be good men, and stay silent.

Your silence buys their continued existence. Your silence means no screams will ever need to be stifled.

Remember my words, but forget me. Leave me to my dark watch. My forever watch.”

Then he climbed back up the slope, stood where he had been standing, and did not turn around again.

Two men who had ridden a controlled explosion out of the atmosphere finished the walk, packed their samples, and flew home.

The third had never left orbit. Nobody ever told him.

The other two never said a word.