Though he has hardly used his Perambulator in Konstance’s memory, her father now spends nearly every waking hour on it, Vizer locked over his eyes, studying documents at a Library table. Mother maps the minutes before quarantine. Did she pass Mrs. Lee in a corridor, did some microscopic fleck of Ezekiel’s vomit land on her suit, could some of it have splashed into their mouths?

A week ago, it all seemed so secure. So settled. Everyone whispering down the corridors in their patched-up worksuits and socks. You can be one, or you can be one hundred and two… Fresh lettuce on Tuesdays, Farm 3 beans on Wednesdays, haircuts on Fridays, dentist in Compartment 6, seamstress in Compartment 17, precalc with Dr. Pori three mornings a week, the warm eye of Sybil keeping watch over them all. Yet, even then, in the deepest vaults of her subconscious, didn’t Konstance sense the terrible precariousness of it all? The frozen immensity tugging, tugging, tugging at the outer walls?

She touches her Vizer and climbs the ladder to the second tier of the Library. Jessi Ko looks up from a book in which a thousand pale deer with oversized nostrils lie dead in snow.

“I’m reading about the saiga antelope. They had this bacteria in them that caused massive die-offs.”

Omicron lies on his back, gazing up.

“Where’s Ramón?” Konstance asks.

Below them images from long-ago pandemics flicker above grown-ups at tables. Soldiers in beds, doctors in hazmat suits. Unbidden into her head comes an image of Zeke’s body being sent out the airlock, then Dr. Pori’s a few hundred thousand kilometers later: a trail of corpses left through the void like breadcrumbs from some ghastly fairy tale.

“Says here that two hundred thousand of them died in twelve hours,” Jessi says, “and no one ever figured out why.” Far down the atrium, at the limit of her eyesight, Konstance sees her father at a table by himself, sheets of technical drawings sailing around him.

“I heard,” says Omicron, staring up through the barrel vault, “that Quarantine Three lasts a year.”

“I heard,” whispers Jessi, “that Quarantine Four lasts forever.”

Library hours are extended; Mother and Father hardly leave their Perambulators. More unusual still, inside Compartment 17, Father has taken down the bioplastic privacy curtain that enclosed the commode, snipped it into pieces, and is using Mother’s sewing machine to make something with it—she hasn’t dared to ask what. Sealed in Compartment 17, beneath the miasma of nutritional paste burping out of the food printer, Konstance can almost smell the collective fear as it moves through the ship: insidious, mephitic, seeping through walls.