I touch a hand to the back of the secret portrait-door before letting Exie re-light her candle. The canvas is backed with wood, a dense enough material not to betray our trespassing by the light we carry. It takes Exie several matches to get the candle going. It trembles as she lifts it; her hands are shaking like aspen leaves. I wordlessly hold a hand out for the candle holder. She relinquishes it.

The staircase we're in must fit entirely inside the school wall. There's no protrusion on the other side, at least that I remember; I'm sure I would have noticed such a thing when we were chasing after willows. But the rose window is inset enough to indicate a thicker wall than I think is typical of gothic architecture, and I no longer hate my father for his speechifying on that matter. I've learned a few things from it, and if those things prove utilitarian in this instance, I'll roll with it.

We've got exactly one direction to go right now, so I point down the staircase and get puppy-dog eyes from Exie. I take the lead. Her fingers surreptitiously grip the fabric at the back of my shirt as we file down the tightly compressed stone stairs. It takes both of us a hand on the wall just to keep from slipping; the staircase is ladder-steep and so narrow, my whole foot doesn't even fit on each step. At least they're not slimy. We've made five or six circuits when the flight abruptly ends. I step gingerly into a low hallway, and grimace as damp seeps through my sock.

Exie gasps. "There's water."

"Where?"

"No, just around. Look."

She tugs my wrist, and I get distracted by that sensation for long enough that I nearly run the candle holder into a wall. When I recover my focus, I see what Exie means. The tunnel wall glistens. Trickles of water run down it like the ground itself is leaking, which is probably exactly what's we're dealing with here. Wet patches make dark spots all the way up the tunnel. And a tunnel it is: long and straight as the line on the map. At the end of that line is the map-blob underneath the school's willows. I think I know what we're going to find down here now.

The tunnel does not echo as Exie and I creep down it. She's still clinging to the seam of my shirt in an attempt to be surreptitious. I let her have it. Definitely not because I want this proximity to continue. By some miracle, I manage to keep our candle aloft and alight all the way down the tunnel, though the same cannot be said of keeping the remaining fabric of my socked feet dry. The dampness is concentrated in patches at first, but by the time we're halfway across the lawn at my estimation, the whole floor glistens. My feet were already chilled by the time we unfolded Barnabas's dove. They've gone numb since then.

The tunnel begins to broaden slightly before we reach its end. My scattered attention picks up on the change, a fact made all the more remarkable by the level of distraction the tunnel's dripping sounds are now giving me. If Melliford Academy tasked a Horror playwright or set designer with recreating a spooky subterranean passageway, they couldn't do better than this.

It's only a dozen steps later that my light stops reflecting off the walls up ahead.

I slow so quickly, Exie nearly runs into my back. Her hand knocks against me, and she lets go of my shirt in what feels like a minor panic. I wait, pretending to watch and listen and not notice her until I feel her grip it again. Only then do I step forward into a cave. My light isn't strong enough to reach its ceiling or other side. The walls swing wide around us, half cut, half natural. The floor is a gently sloping shore of wet rock that ends up ahead. When I lift my light, a reflection winks back at me. I can hear Exie's breathing as I approach with insect's footsteps. It's water. An underground pool, so undisturbed, it might as well be glass. But that's not all that's here.

At the edge of the water is what looks like an altar. That's the only word that jumps to mind for it; it's too low to be a pulpit, and too crude to be artistic for anything but stone-age people. It is made of stone. Rough stones, uncut but fitted together by some bygone craftsperson so they stack firmly without the need for mortar. The flat piece that tops them is soot-blackened. I run my finger over it. No divine energy smites my soul from my body. My finger comes away barely smudged.

"It's old," I say. "That, or someone's washed it."

"There's writing."

"Where?"

She points. Set into the altar's side is another flat stone, this one crammed with tiny, carved text.

"It's in English." Exie lets go of my blazer again and inches around me. She's a little shorter than I am—either a late bloomer, or blessed with a stature that won't draw undue attention to her identity—but she's hunched up so far right now that she widens that discrepancy by several inches. She drifts towards me for a moment, but catches herself and crouches in front of the altar instead. She's reading.

"Old English," she adds. "It's the same dialect as the bible. Oh!" She hops like a small frog, then hops again, closer to the altar this time. "Des? Three hundred years ago."

The lump at the bottom of my stomach turns from stone to lead. "Can you read it out?"

"Here marketh the place, the unholy water beside which rested the Prophet of Miranda when a great Voice came upon Her, saying 'Be not afraid, for I mean Thee no harm. Step into the water, that Thou might receive a vision from The One who lies below; The One once dealt a great injustice for which reparations have never been delivered. Thou hath been judged, and Thy heart found willing. Come to the water, and Thou shalt lead the masses to bring justice for the Fallen who passed from the overworld to the underworld in this place.'"

A nasty shiver passes through me as the pool's black shine turns sinister in an instant. Not that it was ever innocent. I'm not sure anything buried on the grounds of a fallen-angel cult can spare so much as a passing glance at irreproachability.

Exie's finger darts back and forth now, skimming the inscriptions. "'Who seeketh my help?' asked the Prophet, and in that moment, She was possessed by a great sense of the injustice of which the Voice spoke. She stepped into the water, and a vision was bestowed upon Her, the likes of which hath never been written. When She emerged, She spake to the town, saying 'Come to the water, and thou shalt find audience in the court of the highest of judges, the one who will tempt your heart and find it pure or wanting in the eyes of God. The pure shall join this cause, which transcends our mortal realm and gives our lives true purpose.'"

Part of that is the line from the book on witch hunts Exie gave me to read just days ago.

Exie's read-aloud voice is arresting to listen to, lilting naturally until she's nearly singing the words. "The town came, and their hearts were found willing. They wrote of the injustice in a great book and copied its words seven times, the number of the most holy rings of heaven from which The One had been cast. With it, they dispersed to the seven corners of the land to prophesy, that others might join them to rectify the injustice. Here stands the water to which they came to pledge their hearts to these reparations."

Exie has reached the bottom of the little tile. There's a single line there, which she retraces twice before reading it aloud.

"Thus spake Hannah Massingham, the Prophet of Miranda, may She live to see justice dealt as The One is due."

Silence falls between us: a silence so expansive, it spreads to fill the whole cavern with its ringing nothingness.

"The books," I say, and nearly hear the silence shatter at my words. "Seven of them."

"Hannah Massingham." Exie's gaze turns to me, her eyes reflecting the candlelight. "What are the chances they're related?"

"I'd eat my best skirt if they're not." I crouch beside her, acutely aware of the way our arms brush. Exie leans into it, pressing our shoulders together. I give in and reciprocate. The solidity of another person beside me is comforting in the face of the unholy ground on which we stand. Or crouch, as the case may be. We're not being very deferential.

"Exie," I say quickly, as something else catches my eye. I point beneath the tile, where more text carries on over the uncut stone, sprinkled like the formal narrative above it had dandruff. It's fainter than the rest, and slanted like an afterthought. "What does that one say?"

Exie grips my sleeve as she leans down to read it. We're both perched on the balls of our feet on the cold, wet stone. Exie gasps again.

"Another date," she says. "Sixty years, Des. Someone else wrote this one. Thus the fourth descendent of the Prophet of Miranda found the lost unholy waters and took up the mantle of his foremother, She who never lived to see justice dealt, as the Judgment was forestalled by those who refused to believe. Here marketh the consecration of the Fourth Prophet, may He live to see what His mother and all Her successors and all their believers did not."

"The fourth?" I say. My own voice sounds small.

"I know." Exie retraces another line. "Did Hannah die in the Sectant Expulsion?"

"The town of Miranda was wiped from all the maps." Suddenly, everything is making sense except what's right in front of us. "They were preaching to people about helping a fallen angel, outside the Church's purview. Of course the House of Heymair would shut that down. They probably burned the whole town to the ground."

"They tried. Remember the book? They 'donned their holy armor and rode forth to find and purge the coven.' None of them returned."

"That same book said they succeeded later. And there's no town here anymore."

Our eyes meet.

"The Judgment was forestalled,'" I quote. "That has to be it, then. The Sectant Expulsion purged the town."

Exie taps the date on the second inscription. "And killed the original Prophet of Miranda. The demon replaced her three times." She frowns. "But sixty years? If the Fourth Prophet was already a sane adult by then, he's at least eighty by now. If he's even still alive."

"He's old, Exie. Really old. He looks like I could knock him over if I blew on him."

"Who?"

"Headmaster Massingham."

Silence falls again. Exie puts her face in her hands.

"Sixty years ago," I say. "If that was the consecration of the fourth prophet, I'd bet money it's Headmaster Massingham. Three hundred divided by four is only seventy-five. They replace each prophet when the last one dies. This cult's been running underground for the last three hundred years, but it wasn't until this Massingham that they rediscovered the original pool."

"And built the school."

"To feed the cult. With victims for whatever they're doing to justify the demon, or with money. Or both. But there's a book at the center of it; that's where the dove-pages are coming from. Which means it's somewhere in this school."

We're pressed so tightly together now that the click of a door somewhere far up the tunnel makes me whack my head on the altar stones. I tumble back on my rear end, taking Exie down with me. We scramble to our feet together. Exie grips my arm as the pain in my skull makes my head ring. Far up the tunnel we came in along, footsteps have begun their slow way down the stairs. Someone's coming.