Father stands, looking down at the paddle in his hands. Then he hurls it to the ground, hard enough to spray his pants in muck all over again. “Don’t come back in until you’ve finished cleaning this cistern,” he says, his gaze somewhere over my head.

He stalks to the gate in the perimeter fence. Its defensive buzz pauses, then he’s inside, and I’m alone.

I look at the cistern, with its stupid, sloppy, boring mats of microorganisms that stubbornly spread inside. I won’tspend my life cleaning out algae. I fling my paddle down on top of Father’s, hard enough that I hear it crack.

Then I hurl myself to the ground, curl up, and hug my knees until they press against my eye sockets, so I’m almost a sphere like Rover.

Slowly, the heat drains, and takes with it my intense this-discussion-is-the-end-of-the-world feeling. I’m left with the fact that Father and Dad had a bunch of babies that filled them with love and hope, that those kids all died except two of us, and I just threw it in Father’s face because I want to go on an adventure.

I am a bad daughter.

I wish I would cry, so I could prove to this whole boring planet how upset I am.

“Owl.” I look up. My brother is holding out his arm. “Come on.”

Yarrow looks at me with his all-seeing expression and nods, meaninglet’s walk barefoot along the packed dirt and have a sit with our backs against each other so together we can see in all directions and won’t we feel better then?

He and I go sit on one of the smooth, soft slopes, back-to-back. Our usual position. I sift the loose glowing grains of Minerva’s soil between my fingers and enjoy the sensation of my brother’s lungs rising and falling against my ribs. I can feel his bones and the muscles between them.

The wide-open flatness of Minerva spreads out before us.The microorganisms that abound in the soil—the only life we’ve found here, except of course for the malevors—glow in all directions, excited by our friction. Our footprints leave a glowing trail all the way back to the settlement, like Yarrow and I are ghosts. Father’s footsteps have already faded.

Yarrow let me chop off the sides of his black hair yesterday, and he scratches absently at his exposed scalp. There’s plenty of Father in his long-lashed eyes, his sturdy and thoughtful presence. That’s just a coincidence, though, since he’s genetically unrelated to any of us.

“Do you want to tell me about that fight just now?” Yarrow asks.

I shake my head.

“It helps to talk,” he says.

“Don’t even start with that sensitive brother nonsense,” I say, giving him a strong enough shove with my back that he has to reach a hand out to prevent himself from sprawling flat. “It’s the same fight Father and I always have. I don’t want to talk about it.” Playing it safe is one of the family decisions we make so wordlessly now that it’s not a decision anymore, it’s a law. I know that cautiousness can be our doom just as easily as recklessness, but no one else seems to see it.

Yarrow moves to face me, wipes his tunic free of glowing soil the best he can, and rubs his hands together. Slickorganisms bioluminesce along the ridges of his fingerprints. Little Sister glows palely on him, the first rays of Big Sister appearing beneath her. “I hate to tell you, but you did just talk about it,” Yarrow says.

“You think you’re so clever.”

“Don’t worry,” he says, his wide eyes taking on luminous gray-red tints from the rising suns. “Someday you and Father will find something new to bicker about.”

“I’ll cherish the day.”

I do a mental countdown until Yarrow speaks again.Three, two, one.And there he goes.

“There’s good reason they’re terrified about losing us. You know that’s what this is about, right? Father’s not just being a hardnose. He doesn’t want us to have an accident out there and die. They’ve lost too many kids already.”

“Yeah,” I say. “I know.”

Before I’m even aware that I’m doing it, my eyes go to the unmarked spot outside the settlement walls where they buried the babies. Some days the dads will spend a few minutes there, kneeling and whispering, and that’s how we know it’s the birthday of one of our dead siblings. Some emerged from the gestation device gray and unbreathing, their zygotes gone inert during the thousands of years of travel, and some died in their first years of life. Sparrow and Purslane failed to draw enough of Minerva’s air; Thistle fell into a pit; Kestrel never adapted to the extra nitrogenin the atmosphere, her lips nothing but blue; Crane had a fever that left her body only once she was dead. Children one and two, four and six and seven. Every one except Yarrow and me.

Now I feel even worse about my fight with Father. My brother is excellent at making me feel bad. He doesn’t ever try to; he doesn’t need to, he’sthatskilled at it. His constant reasonable goodness is enough.

I stand and reach out to him. He takes my hand, lets me pull him to his feet. “Big Sister is fully up in the sky,” I say. “The dads will be expecting us any moment. Which means you should go.”

“You mean ‘we should go,’ right?”

I hitch my sack over my shoulders, tighten the straps. My spear is lashed to the side as usual, waiting to finally be used. “I meant what I said. I’m going to find a river. Or something.”

“You’re just leaving? Now?”

I make myself look at him. “I’ll be back today. I’m not going too far yet.”