“Oh, that one’s not ours,” Erick replied. “It’s GSAF’s. They have a few security cameras set up on some of the high-priority trenches at the site.” When I looked at the drone again, I could see the words Global Space and Astronautics Federation painted on the side of its body.

Tamara perked up. “What makes Trench 9 a high-priority area, Professor Gomez?”

He grinned at her. “Well, not the arch, even though I know the two of you love it. It’s because of some other stuff we’ve found in this area. Every once in awhile we’ll uncover fragments from old satellites or probes, mostly from NASA and the Soviet space program and such. Those are GSAF property, so we have to turn any we find over to them.”

“GSAF is that interested in retrieving broken pieces of junk from abandoned missions?” I asked doubtfully.

Erick shrugged. “This is their land, Isaak. This whole mission is on their terms. If they want broken pieces of junk, that’s what I’ll give them.” As he spoke, he fiddled with something on his palmtop. The laser grids in Trench 9 flickered, then powered on. “All right, if the two of you could work on this quadrant, please.”

The area he’d marked off for us was further down the dried streambed, about as far from the arch as we could get while still working in the same trench. I looked at the rock formation longingly.

There was nothing we could do about it, though. We’d have to wait for Erick to get distracted before we could move closer. I slid on my goggles, pulled out my spade and started digging.

Two seconds later, Celeste was standing over my shoulder. “Zak, can I help you be a arky-ologist?”

I sighed. Had it really been necessary to bring her along? “I don’t think so, twerp. This isn’t a game. We have to be really careful.”

“I can be careful!”

“Yeah, right. You can’t even play with your Barbies without one of them winding up decapitated.”

“That’s not true!” She didn’t even know what the word decapitated meant, but obviously my tone had gotten through, because her face was red with indignation now.

“You can help me, Celeste,” interrupted Tamara. Celeste beamed and raced over to her like a puppy. “Here, can you hold my kit for me? Okay, so when I dig, I need to put the dirt from my shovel into this box. See? Then we bring it over there”—she pointed to a pile on the side of the trench—“for Dr. Erick to go through later. That’s called backdirt. We have to go through it again, in case I missed anything when I was digging here. It’s really important, so I need you to be careful when you carry this, okay?”