"Did you boys hear or see the ship that passed over us this morning?"
"Ship?"
"No, we didn't see nor hear a thing. Sure it was a ship?"
"No, I didn't see it, either. I thought I heard one, and ran to look out, but couldn't locate anything. Maybe it was just my imagination."
"Spaceship or airship?" Jon asked.
"I couldn't tell you that, either, except that if I did really hear one, it must have been a spaceship to disappear so quickly."
"Unless it was a fast jet—they're just as hard to spot."
They discussed the affair for some time, but could come to no conclusions. If it was a ship, why hadn't it stopped or signalled? And if it wasn't one, what had she heard? Or had she actually heard anything?
Two evenings later the two boys had completed outlining their city site, and were just climbing into the Star Rover when they heard their mother's voice.
"That you, boys? Come in here. Hurry!"