“Why do you have this?” I ask Yarrow. My eyes go to the settlement behind him, looking for gaps in the fence, for the horns of ravaging malevors. There aren’t any immediate signs of crisis.

Yarrow finally speaks. “I don’t know.”

“What do you mean, you ‘don’t know’?”

“I just... came to... out here, with it. When I saw you approaching. It’s like I just woke up. I don’t know what’s going on with me!”

I hear the trill of panic in his voice. He’s not jokingaround. “Hey, it’s okay,” I say.

OS speaks. “His vitals are healthy, except for the elevated pulse expected with a high level of stress.”

I cross the final steps and hug my brother. “It’s okay, we’ll figure out what happened to you. Maybe you got food or gas poisoning, but you’ll be fine. Are the dads okay?”

“I don’tknow!” he wails, sharp and loud.

“Shh, shh,” I say, holding him. “We’ll figure it out. I’m sure everything is fine.”

“Where have youbeen?!”

“You’re making me nervous,” I say. “You know where I’ve been. Please relax for now, okay? How long have you been this way? Hush, don’t answer yet. Concentrate on breathing. That’s it.”

He does as I ask, resting his chin on my shoulder and giving long inhales and exhales. I take in his thick brother scent, slightly gross and slightly sweet. While I do, the post flexes under my fingers and my mind races. What could possibly explain this?

“I’m investigating the fence integrity,” OS announces as Rover hovers off toward the settlement.

“Let’s go with OS,” I whisper. “This piece of polycarb belongssomewhere. We should put it back.”

He nods, and draws away. I give him a kiss on the cheek before he’s out of range, and then slot the fence post beside the alien log on my back.

OS peels off as we approach, away from the safe entrance and toward the malevor territory on the south side. “No, no,no,” I curse as I break into a sprint.

Yarrow gasps. “I didn’t do anything, I swear it.”

I don’t know what to think, so I don’t answer. We curve around the fence.

There, just ahead, two panels of the perimeter have parted. It looks like an open book, only the pages curve away from an open space, through which a human or a robot—or a malevor—could easily fit.

I want to call out the dads’ names, but before I do I look to the malevor territory... and see them. They’re a good hundred meters out, but their attention is focused on Rover, Yarrow, and me. The two biggest males raise and lower their front hooves. Agitated.

“The missing post means the circuit is broken, and the pneumatic guns are no longer active,” OS says. “It does not appear that the malevors are aware of that fact yet. We are in the window where they are still scared of the fence, and we shouldn’t lose that advantage.”

“Where are Dad and Father?” I ask.

“I am unable to detect them from here. Come inside now, before the malevors approach. Hurry!”

My thoughts churn in too many directions for me to decide. Luckily OS doesn’t get baffled; it weighs variables and makes choices in the space of microseconds. All I haveto do is listen and obey. Yarrow and I follow along, to the parted fence.

The sharp-horned malevors start toward us. “Quicker!” OS says.

Rover floats through, then Yarrow tumbles after. I’m the last in. I whirl around and hold the two lengths of fence together. Since I’m facing out, I have a perfect view of the approaching beasts, thundering closer. “Yarrow, take the post and slot it through.”

I don’t feel anything at my back. “Yarrow!”

Then his fingers are against my spine, and I can feel the post sliding up from the carrying loop. My brother’s hands enter my field of view as he passes the post through its brackets.

“Step back!” OS orders.

The fence buzzes. The pneumatic guns dip back and forth as they initialize, then the nearest one fires into the soil a few paces before the charging malevors. They skid to a stop, then bolt back to their females and young.