Deep Cost

October 31, Time Unknown, Stonehenge

Adam Clarke

The battlefield was quiet, but it stank of blood and a smell I couldn’t quite recognize. Ozone?

I walked among the wounded, my legs moving on autopilot while my mind tried to process what we’d just survived. Golden-robed figures from Mahoutokoro moved with practiced efficiency, their healing spells weaving patterns of light over broken bodies. The contrast was jarring— their serene countenance against the backdrop of shattered stone and scorched earth.

An Ilvermorny student— John Culder, his name came to me with harsh self-reproach— lay under a conjured shroud near the cave entrance. Fifteen years old. Dead protecting his friends from a Killing Curse he’d had no business facing in the first place. I saw Neville sitting quietly beside the shroud covering Susan Bones.

My eyes hardened. I had warned them. It wasn’t my fault.

You led them here. You convinced them to follow you into this hell.

My hands were shaking. I shoved them into my pockets before anyone could notice.

“Clarke-san.”

I turned to find Akio approaching, his robes flowing about his form. His Kirin stood behind him, its scales gleaming despite the carnage surrounding us. The creature’s presence felt wrong somehow— too pure for a place soaked in this much death.

“Akio.” I managed, my voice rough from shouting orders during the battle. “Thank you. If you hadn’t arrived when you did—”

“We may have made a grave error.” He interrupted, his expression more serious than I’d ever seen it. “The barrier system was not merely defensive.”

I blinked, my immediate tiredness making it hard to follow. “What do you mean?”

“It was containing something.” Akio glanced toward the shattered cave entrance, where darkness seemed to pulse with unnatural rhythm. “The power emanating from the mouth of this cave— it is expanding. Growing stronger. When we destroyed those barriers…”

He paused, choosing his words carefully. “We may have accelerated Grindelwald’s work instead of stopping it.”

The words hit me like a physical blow. All this— The deaths, the wounded lying around us— and we might have actually helped Grindelwald?

“You’re saying we shouldn’t have broken through?” My voice came out harsher than I intended.

“I am saying the situation is more complex than we understood.” Akio’s dark eyes met mine with uncommon sympathy for someone who’d wanted to kill me less than a year ago. “The energy readings my colleagues are detecting… they suggest the ritual has entered its final phase. Whatever Grindelwald intends to accomplish, he will accomplish it soon.”

A cold draft brushed against my mind— so faint I almost missed it. Like someone whispering from the next room, words just below the threshold of understanding. I shook my head, attributing it to exhaustion and stress.

“Then we need to move fast.” I said. “Get down there and stop him before—”

“Before he does something even worse than the destruction of the Americans’ nation.” Akio finished quietly. “Yes. That would be advisable.”

The whisper came again, slightly clearer this time. Not words exactly, but a sensation— like recognition, like something ancient acknowledging my presence. I rubbed my temples, forcing myself to focus on Akio’s concerned expression.

“Are you well?” He asked.

“Fine. Just tired.” I straightened, pushing the strange sensation away. “Your people— will they be able to fight if we need to push deeper?”

“My squad will accompany you into the depths.” Akio confirmed. “Though I must warn you, Clarke-san— the magical energies below are unlike anything in our traditional teachings. Whatever awaits us down there exists outside the normal boundaries of our art.”

“Story of my life lately.” I muttered.

A shout from near the cave entrance drew our attention. Tonks was organizing the survivors. Mad-Eye Moody stood beside her, his magical eye whirring as it scanned the darkness beyond the shattered barriers.

“Listen up!” Tonks’ voice carried clearly over the groans of the wounded and the quiet conversations of those still capable of fighting. “We’ve got maybe an hour before Grindelwald completes whatever he’s doing down there. We’ve also got some new information. Dumbledore’s reinforcements are still dealing with the other attacks— we’re on our own until they can break free.”

One hour. Many had died, with some others who lay unconscious with injuries that might never fully heal, Susan, and others dead— all for sixty minutes.

“We’re splitting into three groups.” Tonks continued, her Auror training overriding whatever emotions she might be feeling. “Moody takes point with the remaining Aurors. Akio’s squad provides magical support and aerial reconnaissance where the tunnels allow. Clarke— you coordinate the students who are still combat-capable.”

I felt eyes turning toward me. Harry, standing with Hermione and Ron near a cluster of wounded Gryffindors. Draco, alone but unbroken, his expensive robes torn and smoking. The Weasley twins, their usual humor buried under grim determination.

I resisted the urge to tell them to stop and rest here. It would only get uglier from here on out. I couldn’t do that; I wouldn’t.

The whisper brushed my mind again, stronger now. This time I caught fragments— not words in any language I knew, but meanings. Power. Purpose. Recognition.

I shoved it away harder.

“Clarke?” Tonks was looking at me expectantly. “You good to lead?”

Was I? Every muscle in my body ached. My magical reserves felt depleted to dangerous levels. And something in the depths below was apparently calling to me in ways I didn’t understand and definitely didn’t trust.

But I looked at the faces around me— young people who’d followed me into hell once already, who were somehow still standing, still willing to fight.

“Yeah.” I said, my voice steadier than I felt. “I’m good.”

Tonks nodded sharply. “Right then. Five minutes to redistribute supplies and check your gear. Then we go down, and we don’t stop until Grindelwald’s ritual is ended or we’re all dead. Clear?”

A ragged chorus of acknowledgement rose from the survivors.

I caught Akio’s eye as the groups began to organize. He inclined his head slightly— a gesture of respect that felt simultaneously earned and utterly undeserved.

The tunnels were worse than I’d imagined. Not even five minutes, and we’d been forced to separate.

Narrow stone corridors twisted deeper into the earth, their walls carved with runes that seemed to pulse with sickly light. The air tasted wrong— metallic and cold, like breathing in the aftermath of a lightning strike. Every breath made my lungs ache.

I’d taken point with Harry, Hermione, Draco, Tony, Daphne, Sarah Chen from Ilvermorny, and the Weasley twins. Behind us, Mira, Ophelia, and of all people, Blackthorn Jr, though he seemed much subdued. Twelve of us total, moving through darkness that felt actively malevolent.

Su will be fine. I thought. She, and many others had understandably been too shaken by the experience to venture further into the caves, though they had agreed to help keep the peace at the surface, and coordinate any future reinforcement.

In their own ways, they were still helping, which I was eternally grateful for.

Still, there was something to deal with.

“Hold.” I whispered, raising my fist. The group stopped immediately, wands raised.

I could hear movement ahead— the scrape of boots on stone, whispered commands in the distance. Some of Grindelwald’s people, preparing an ambush in the elevated alcoves I could just barely make out in the dim light.

My mind was already calculating angles, trajectories, defensive positions. But there was another calculation running parallel.

We couldn’t afford prisoners. We couldn’t afford to leave enemies at our backs. I turned to face my group, keeping my voice low.

“Listen carefully. What I’m about to say—” I paused, listening for any noise ahead for a moment before resuming. “No stunners. We’re outnumbered and we can’t spare people to guard prisoners. If they attack us, we respond with lethal force.”

The silence that followed was deafening.

Hermione’s face went pale. “Adam, we can’t just—”

“We can and we will.” I cut her off, my voice harder than I’d ever used with her. “They’re going to try to kill us. They’ve already killed people we care about. I’m not asking you to murder anyone in cold blood, but if it’s them or us, I need to know you’ll choose us.”

“That’s—” She started, but Harry’s hand on her arm stopped her.

“He’s right.” Harry said quietly, and something in his tone suggested he’d already made this calculation himself. “Susan’s dead because we hesitated. Because we’ve been treating this like a duel instead of a war.”

Draco’s expression was unreadable. “My father’s people don’t take prisoners. They never have. If we’re going into their territory, we play by their rules or we die.”

Greengrass said nothing, but her jaw tightened and her grip on her wand shifted. Acceptance, or at least understanding.

“Considering I’ve already tried to kill you— I’ve got no problem with it.” He said, ignoring the glares from Ophelia and Mira.

The Weasley twins exchanged one of their wordless communications before Fred— or maybe George— nodded. “We’re in. Just… make it clean, yeah?”

“As clean as I can.” I promised, though the words felt hollow.

Ophelia looked sick but determined. Mira just nodded.

“We move on my signal.” I whispered. “Harry, those alcoves at ten and two o’clock. Twins, the ledge directly ahead. Everyone else, take cover and watch for flankers.”

The ambush, when it came, was textbook— exactly the kind of coordinated assault that worked against inexperienced fighters. Death Eaters and Grindelwald’s acolytes emerged from concealment simultaneously, their Killing Curses painting the tunnel in sickly green light.

But we weren’t inexperienced anymore.

I didn’t cast a spell— not immediately. Instead, I transfigured the stone beneath the nearest attacker’s feet, turning solid rock into liquid mud that swallowed him to the waist. While he struggled, Harry’s blasting curse took him in the chest. The man’s scream cut off abruptly.

The alcove at two o’clock was already empty; one of the twins had collapsed the stone overhang, and the grinding sound of rock crushing flesh told me we wouldn’t have to worry about that position anymore.

An acolyte in gray robes inched through the shadows, almost imperceptible as her wand was trained on Hermione. I was already moving, a Jelly-Legs Curse causing her to go down with a thud. Draco’s follow-up curse, a puke green jet of light, struck her in the chest.

She didn’t get back up.

It was over in perhaps twenty seconds. Six enemies dead, and our group intact.

I stood in the aftermath, staring at the woman I’d essentially killed. She was young— maybe mid-twenties, with the kind of delicate features that suggested a privileged upbringing. Someone’s daughter. Possibly someone’s sister or wife.

Now just another corpse in a tunnel that already reeked of death.

My hands weren’t shaking anymore. That might have been worse than if they were.

“Adam?” Hermione’s voice was small, uncertain. “Are you— “

“I’m fine.” I lied. “Check for survivors. If any of them are still conscious, we need information about what’s ahead.”

But there were no survivors. We’d been thorough.

The silence stretched out, broken only by our breathing and the distant sounds of combat from other tunnels. Someone— I think it was Ophelia— bent over and vomited against the wall. No one commented on it.

I forced myself to look at each of their faces. Harry’s expression was grim but resolute. Hermione looked like she was reassessing everything she thought she knew about warfare and morality. Draco seemed almost bored, which meant he was probably more affected than he wanted to admit. The Twins were standing shoulder to shoulder like they were holding each other up.

I couldn’t let them think.

“Keep moving.” I said quietly, my voice barely above a whisper. “Watch your spacing. Next time might not be an ambush— might be a full defensive position.”

We moved deeper into the tunnels, stepping over the bodies we’d created. Behind us, the runes on the walls seemed to pulse brighter, as if feeding on the fresh death.

The whispers brushed my mind again, and this time they felt almost… approving.

Go away.

As I feared, the tunnel network was a maze designed by someone who understood exactly how to break an assault force into manageable pieces. Grindelwald had truly made things as difficult as they could possibly be.

Every few hundred yards, the passages forked. Sometimes two directions, sometimes three. Sometimes, they rejoined. The strategic nightmare was obvious— split your forces to cover more ground and risk getting overwhelmed by concentrated enemy resistance. Stay together and let the enemy choose the battlefield while their ritual continued unimpeded.

Luckily, Moody was smart, using the Patronus Charm to coordinate between the groups. We’d been underground for another ten minutes when we all linked up once, again.

The bad news was that we’d hit another major fork.

“Three tunnels.” Moody growled, his magical eye spinning as it tried to penetrate the darkness ahead. “Can’t see more than fifty feet down any of them. Magical interference is getting worse the deeper we go.”

Tonks was breathing hard, a nasty burn across her shoulder from our last engagement. “We have to split up again. We don’t have time to clear each path sequentially.”

I hated that she was right.

“There’s only one choice. One squad takes the left passage— Moody.” I said, falling into tactical planning like it was the only thing keeping me sane. “Akio, your squad takes the right— the ceiling’s higher there, your kirin might have room to maneuver. We’ll take the center.”

“And if one group runs into the main force?” Draco asked, his voice tight.

“Send up signals and fall back.” Tonks replied, agreeing. “We regroup and hit them together.”

It sounded reasonable. It sounded like a plan that might actually work.

It was a lie, and we all knew it. If any group ran into serious resistance, they’d be dead before reinforcements could arrive.

“No better plan for a situation like this.” Moody growled, his good eye pinning me for a moment. “Stupid, likely to get us all killed. You kids’ll be dead within a minute.”

“You’re probably right.” I agreed. “But there’s no need to ruin your own chances because of us.”

Both Moody and Tonks seemed displeased by this, but I was right and they knew it. And so, we split up again.

The center tunnel felt different from the entrance corridors. The walls here weren’t just carved— they were grown, like the stone itself had been convinced to flow into these shapes. The runes were more complex, layered in patterns that hurt to look at directly. And the temperature was dropping with every step we took.

“Water ahead.” Harry said suddenly, and I realized I could hear it too— a rushing sound that echoed strangely off the walls.

The tunnel opened into a cavern. An underground river cut directly across our path, maybe thirty feet wide and moving fast enough that I could see white foam where it churned against submerged rocks. The only way across was a series of stone pillars rising from the water, spaced just far enough apart that you’d have to jump between them.

“That’s not good.” Hermione said immediately. “We’ll be completely exposed while crossing.”

She was right. Anyone positioned in the shadows on the far side would have easy targets.

“Maybe not.” Fred said, taking a step forward and waving his wand at the pillars. “Defodio!”

A jet of blue flew into the base of a pillar, and I understood his intent— he wished to create a bridge. It wasn’t to be. The pillar absorbed the spell, the runes inscribed upon it flaring slightly before calming down.

Frowning, Fred tried again, with George joining him. Again, no effect.

“I guess there’s no choice.” I patted the boys on the shoulders before stepping forward, already analyzing the spacing between pillars. “I’ll go first. Harry, you’re second. Everyone else follows in pairs. If shooting starts, Shield Charms up and keep moving.”

I didn’t wait for arguments. My first jump was solid, landing cleanly on a pillar that barely had room for both feet. The second jump was longer, and I felt my boot slip on wet stone before I caught my balance.

Halfway across, I heard it.

Not the whispers this time— actual voices. Coming from the water itself, rising and falling with the current’s rhythm. They weren’t speaking English, weren’t speaking any language I recognized, but I understood them anyway. They were singing about drowning, about the weight of water in your lungs, about the peace that came when you stopped struggling.

“Don’t listen to the voices from the water!” I called back to the others, forcing myself to focus on the next jump. “The water’s enchanted. It wants you to fall.”

Harry made it across behind me. I sent him a quick glance, able to see the strain in his face— whatever he was hearing, it was personal. Hermione was halfway across when the attack came.

Three figures materialized from alcoves we hadn’t seen, their wands already moving. Killing Curses and Blasting Hexes filled the air, and Blackthorn Jr.— still on the near shore— threw up a Shield Charm that probably saved his life but sent him stumbling backward.

“Move!” I screamed, sending a Blasting Curse toward the nearest attacker. The spell went wide as I tried to maintain my balance on the narrow pillar, but it bought Hermione the seconds she needed to make her final jump.

Draco and Ophelia were caught in the middle. A Blasting Curse struck the pillar between them, and Ophelia went into the water with a scream that cut off abruptly as the current took her.

“Ophelia!” Mira’s anguished cry from the far shore hit me like a physical blow.

Draco had fallen as well, though he’d managed to scramble and cling to one of the rocks. He wouldn’t stay there for long.

I was already moving, transfiguring stone from the riverbed to create a dam, anything to slow the current, but the water was moving too fast and my magic felt sluggish, like the river itself was fighting my attempts to control it.

Accio! I cast instead, summoning Draco’s clothes; he flew above me, straight towards safety. He fell to the harsh stone floor, soaked and shaking. Mira and George were still on the far side, pinned by enemy fire that was growing more accurate.

“Sarah, Blackthorn— suppressing fire on those alcoves.” I ordered, my voice mechanical. “Harry, can you reach Mira and George?”

Harry’s response was a wave of ancient magic that didn’t just suppress the enemy positions— it collapsed them entirely. Stone groaned and fell, burying our attackers in tons of rubble.

Nothing but the sound of rushing water followed. The most immediate danger had passed, but Ophelia was gone, swept away by currents that led to underground tributaries we’d never map. Drowned or battered to death against submerged rocks— either way, she was dead and there was nothing we could do.

I continued to hop across the water, ignoring the voices which promised a reunion with our dead friend.

“Don’t listen to the voices!” I insisted again as I made it to the other side. “It’s just a trick!”

Before long, everyone had crossed. Mira made it across in a state I’d never seen her in— silent, hollow-eyed, moving like a puppet with cut strings. Draco stayed close to her, one hand on her shoulder, saying nothing because there was nothing to say.

We kept moving.

The tunnels forked again. Then again. Twice more we reunited with Tonks’ group, and each time there were fewer people. An Auror named Denzel had taken a killing curse. Two of Akio’s wizards were missing, their kirin returned without riders. Tonks herself was limping slightly, a Severing Charm having clipped her leg during an ambush in a corridor filled with animated shadows.

The shadows had been the worst. They’d moved independent of any light source, flowing across walls and ceiling like living things. Three of the Officers had been dragged into the darkness screaming. We’d managed to dispel the enchantment, but by then it was too late.

I stopped counting our casualties.

The third reunion happened in a chamber where the walls themselves seemed to breathe— expanding and contracting in a rhythm that matched no human heartbeat. We’d lost Akio’s second-in-command, a stern woman whose name I’d never learned. Moody had a gash across his face that had barely missed his good eye. A few of the Officers were wounded badly enough that they should have been evacuated, but there was nowhere to evacuate to.

My own group had shrunk to seven. Ophelia was presumed dead. Blackthorn, to his credit, had taken a severe Cutting Curse across his arm for Mira. Ophelia’s death had hit him harder than I realized. While Mira was trying to stop him from bleeding out, he admitted that she should just let him die for all his mistakes.

“Shut up!” Mira said. “You idiot! This is all your fault! She was miserable because of you, so shut up and help us if you want to show you cared!”

Blackthorn kept quiet, then, letting her do whatever she wanted. Seeing him so beaten was something I had wished for in the past, but now, I only found him pitiable. The Twins did what they could, but wisely realized that none of their jokes would be taken with any form of good humor, here. I gathered what remained of our force in the center of the breathing chamber, trying to ignore the way the walls seemed to be closing in incrementally with each pulse.

“We can’t keep splitting up.” Hermione said, too exhausted to soften the words. “We’re dying in pieces.”

“We’re dying anyway.” Draco said flatly. “At least this way some of us might get through.”

“He’s not wrong.” Tonks admitted, her voice rough with pain. “If we bunch up, one good ambush could wipe us all out.”

I looked at the faces around me. Harry, barely staying on his feet. Hermione, her methodical mind working overtime to analyze tactical situations that shouldn’t exist. Greengrass, who’d been quiet and determined despite everything we’d seen. Mira and Blackthorn, broken but still holding their wand steady. The others— all of them running on willpower alone because there was nothing else left.

Their hands were trembling. Their eyes were hollow. They looked like soldiers who’d been fighting for days instead of hours.

We were running on fumes, on adrenaline, on the desperate hope that if we just kept moving forward, eventually we’d reach something that made all this death meaningful.

“There are too few of us now. We stay together.” I said finally, making the call even though I wasn’t sure it was the right one. “We move as one unit. Whatever’s ahead, we face it together.”

The whispers brushed my mind again, stronger now. This time they carried something that might have been approval, or amusement, or anticipation.

I was too tired to care which.

“Let’s go.” I said quietly. “And keep your eyes open.”

Behind us, the breathing walls pulsed one final time, and I could have sworn I heard them sigh. The tunnel opened into hell. I’d thought the breathing chamber was vast. I’d thought the barrier system outside had been impressive. I’d thought I understood the scale of what we were facing.

I’d been catastrophically wrong.

The cavern before us stretched so far in every direction that the walls disappeared into darkness our wand-light couldn’t penetrate. It wasn’t a cave— it was an underground city. Stone bridges arched overhead in impossible geometries, crisscrossing at heights that made my stomach lurch just looking at them.

Massive pillars carved with those same pulsing runes rose from the cavern floor like the bones of dead gods. And hanging from the ceiling, suspended by magic I couldn’t begin to understand, were banners— hundreds of them, depicting Grindelwald’s symbol in silver thread that caught and reflected the sickly green light emanating from sources I couldn’t identify.

But it was what occupied the cavern floor that made my blood freeze.

Soldiers. Hundreds of them. It could have been two hundred, or four— the darkness made it impossible to get an accurate count. They were organized in formations that I recognized from my time in their camp. Grindelwald’s acolytes in gray, and Voldemort’s Death Eaters in black.

“Merlin’s saggy left—” Tonks breathed, her words trailing off into shocked silence.

“This isn’t a defensive position.” Hermione said, eyes wide with terror. “This is an army. They’re not trying to keep us out— they’re preparing to march out.”

She was right. This wasn’t about protecting Grindelwald’s ritual. This was about what came after. When he opened his gateway to the Abyss and claimed whatever power he sought, this army would pour out of Stonehenge and sweep across Britain like a plague.

And then, the rest of the world.

“How many do we have?” I asked Moody, not taking my eyes off the assembled forces below.

“Counting everyone? Maybe forty five.” He growled.

“Forty against…” Tonks said, but didn’t finish. She didn’t need to.

I should have called for a retreat. We couldn’t stop the ritual with this many people ahead of us. The mission had failed. Retreat would be the smart move, the sane move.

Instead, I heard myself say: “We make them bleed.”

Harry turned to look at me like I’d lost my mind. Maybe I had.

“We can’t win this.” Draco said flatly. “Even if Dumbledore himself was here, we couldn’t win this.”

“We don’t need to win.” I replied, my voice steadier than it had any right to be. “We just need to buy time. Slow them down. Make them commit forces to dealing with us instead of preparing for whatever comes next.”

“That’s suicide.” Tonks said, though there was something in her expression that suggested she understood the logic even if she didn’t like it.

“Everything we’ve done today has been suicide.” Daphne said quietly, speaking for the first time since she’d followed us here. “At least this way we take some of them with us.”

Tonks was staring at me with an expression I couldn’t quite read. “You know what you’re asking?”

“I know exactly what I’m asking.” I met her gaze steadily. “I’m asking you to die with me. To make it hurt. To make them remember that we were here.”

The silence stretched out. Somewhere below, orders were being shouted in multiple languages. The army was beginning to move, formations shifting with practiced precision.

“I like this plan. Right then.” Moody said finally, a grim smile crossing his face. “Aurors— battle line formation. Mahoutokoro— aerial support, hit their command structure first. Students—”

Here, he paused, looking at the young faces around us. “Stay behind the adults. Focus on survival. If you get a clean shot, take it, but don’t be damned heroes, or I’ll kill you myself.”

“Bit late for that.” Blackthorn said, the first words he’d spoken since Mira had chastised him. His voice was flat, emotionless, already dead inside.

Akio’s remaining wizards were mounting their kirin, golden robes rippling as they prepared for battle. The creatures sensed what was coming— I could see it in the way they shifted and snorted, their scales catching the green light like polished armor.

“We may die here, but it is for a great, and honorable purpose.” Akio said, and the young man was smiling as he looked around at us. “I can think of no better companions.”

Some smiled, others inclined their heads.

“Thank you, Akio.” I said.

Below us, the enemy army had spotted our position. Wands were being raised. Spells were being prepared. In seconds, we’d be facing a magical barrage that would make everything we’d survived so far look like practice dueling.

“For everyone who didn’t make it this far.” I said, raising my wand. “For Ophelia. For Susan. For everyone they murdered today. We make them pay.”

The first volley of spells came up at us like a wall of light.

And we charged to meet it.

“Kill them all!”