have mistaken the protruding tip of her bow for a sapling. But it moved slightly, when she turned to survey the hill below her. Anyone who stepped from the long grass of the plain would be dead before they got within fifty yards of the door.
Parting the grass with both hands, I scraped the snow clear, closed my eyes, and pressed my cheek against the iced ground, and tried to get a feel for the overall shape of the Ark that lay below. It took me a few moments to work out why it felt familiar. Then I recognized it: it was like the island, but inverted. Where the island had been a cone rising from the sea, this was an upside-down cone, tunneling down to a central point. The outer corridors, at the surface level, traced a rough circle, several miles in diameter. Within this ring, narrower and deeper, a network of rooms and corridors burrowed. A nest of circular corridors, ever smaller and more deeply sunken. Even the outer ring of the Ark wasn’t close to the surface. In front of us, beyond the buried door, a passageway dropped steeply to join the outer corridor. And there was a symmetry to the Ark’s layout, I realized, as my mind fumbled its way through the stone and steel. The passageway to the surface was repeated, at equal lengths around the Ark’s circular rim.
“Remember what the papers said,” I whispered to Piper. “The radiation measurements were taken from Ark Entrance 1. There are other entrances. I can feel three more, around the outer circle. One at each of the compass points, more or less.”
For the rest of the day we edged around the rock-strewn hill, crouching in the deep grass. Three times I sensed a passageway climbing to meet the air. But each time, when we crept close enough, we were greeted by the same sight: guards, swords, and bows. In front of the western door was a cluster of tents—enough to quarter at least a hundred soldiers.
The southern door, closest to the river, had been spared the hill’s advances, and instead of a messy excavation, a steel structure was visible, at ground level, although rusted. It was circular, more a hatch than a door, and was the height of two men. It looked as though the Council had blasted it open, somehow: a hole was torn in the center of the hatch, edged by sharpened spurs of metal, reaching inward like monstrous teeth.
When we’d retreated out of sight of the door, Piper exhaled slowly, closing his eyes for a moment. “We’ll have to come back, with troops. Even with Zoe, we could never have taken one of those entrances. And even if we did, we’d only be trapped as soon as we entered.” He kicked at the snow. There was no time for this. No time to make the risky journey back to New Hobart, and to return again. No time for another battle, and more blood. How much luck, and how much time, did we have left? The Council’s soldiers in the Ark were excavating more knowledge, more power, every day—and each day, the refuges swelled with more Omegas.
Piper sat on one of the boulders, and gave a desolate laugh. “That poor bastard, Heaton, died trying to get out of this place, and here we are, struggling to get back in.”
At Heaton’s name, my head jerked upward.
“There’s one more entrance.”
He sighed. “Is there any point? They’re not going to have left a door unguarded.”
“It’s not like others. It’s not a door,” I said. “It was what you said about Heaton that reminded me. Remember what the Ringmaster found in that report, about the guy who’d killed Heaton when he tried to get out?”
Piper nodded. I’d told him and Zoe about the Ringmaster’s discovery, and the conclusion to Heaton’s story.
“It said something about where it happened,” I went on. “Something about him being killed while trying to get into a ventilation shaft. I didn’t know what it meant—didn’t really think about it. But it means he wasn’t trying to get out through one of the main doors. It makes sense—they’d have been carefully guarded. He was trying to escape another way.”
“This ventilation shaft—so a kind of underground chimney?”
“I guess so. They must have needed to get fresh air down there, somehow.” A chimney was what it felt like, now that I trained my seeking onto it: a passage to the surface, both smaller and steeper than the main entrances.
“Is