The Friendly compy didn’t hesitate. “Yes, Master Louis.” He removed the equipment he had brought, briefly accessed his instruction files so he knew how to use the tools, then scrambled up the nearest shallow ledge. With his nimble mechanical legs, the little robot zigzagged his way higher.

Louis watched DD, then glanced back at the bulky Klikiss robots, knowing they couldn’t possibly make the ascent. “Sorry, Sirix. You three will have to wait until we erect ramps.”

“If we decide to erect ramps. We have to see what’s up there, first,” Margaret said. “May not be worth the effort, old man.”

Louis gestured to the green priest, smiling. “Arcas, would you like to go next? Since this is your discovery, you might as well have the honor of being the first human to set foot there.”

The green priest looked surprised and then embarrassed. “Are you sure it wouldn’t be better if you or Margaret—”

“Arcas, we don’t care about such things,” Margaret said with a hint of impatience. “Go on.”

The green priest scrambled up after DD, using the handholds and pitons the silvery compy had diligently left for them.

Fat, cold droplets of gray rainwater splattered against the cliffside as Margaret began to climb, waiting at each ledge for Louis. She knew they would both be sore this evening. They would take turns rubbing muscle balm into each other’s aching joints, but an excellent discovery would help her get over any amount of pain and weariness.

DD had reached a ledge three-quarters of the way up the cliff face, and the rain continued to splatter harder. After pounding a thick piton anchor into a crack, he called down. “I will drop a support rope. This last section appears to be very precarious.”

Then a burst of rain slammed into the canyon like a fire hose, pounding against the stone and washing loose mud and sand down in sheets like oozing paint.

“Hang on!” Louis said, and pushed Margaret close to the wall, giving her the advantage of minimal shelter. They were all drenched within moments, but the rain did not lessen. Rivulets poured through cracks in the canyon wall, leaching alkali from the stone. The air smelled thick and slippery, like soap and ashes.

“I hear something.” Arcas raised his voice above the sizzling sound of sharp raindrops, like meat frying on a hot grill. “Listen. It’s getting louder.”

Margaret heard a crash and rumble, a splashing growl that increased in intensity. Clutching the rough cliff, she looked down to see a boiling tongue of brown water surge through the narrow canyon. The flash flood came with the force of a stampede, carrying silt and boulders like projectiles. It slammed against the lower wall, ricocheted and swirled up, licking the layered rocks.