Very slowly, I retreated.

“Will?” I whispered.

Will switched on the penlight he kept attached to his belt.

“Switch that off!” the voice rapped.

Will directed the light towards the sound and the slender beam picked out two girls huddled together. One was holding a large knife. She kept her other arm around the girl beside her.

“We won’t hurt you,” Grady said.

“Put down the knife.” I held up my hands, trying to look non-threatening. “Are you Prisha? I think we saw your team earlier.”

The girl shook her head. “Somia.”

“What happened? Where’s the rest of your team?”

The knife tip tilted downwards. “Who d’you think we’re hiding from?” Somia glared. “Liam and Sanjay wanted to take Pasha’s finger. I told them we’d do it in the morning. Then, when they were making camp, we ran.” Her eyes went to Carmen, who was sat at the edge of the pool of light, tears welled and the knife swept back up. “You did that to her?”

“No!” Lizzie crawled to my side. “We’re hiding from the people who did … and from the team who were chasing us.”

“We’re hiding from everybody,” Grady muttered.

“Well, you can’t stay here.” Somia gestured. “This is our place. Find somewhere else.”

“Why don’t you come with us?” Lizzie begged. “You’re not safe alone.”

“Says you!” Somia glowered. “You can only find this hiding place if you actually climb into the ditch. And if someone does try to drag us out, they’ll get cut. We’re safe enough until the competition’s over. One more day. Then we’ll come out.”

“You’d be better off with us. We can protect you.” Will flicked his hair and offered her one of his rare smiles.

Somia stared for a second. “Yeah? Like you protected her?” She pointed the knife at Carmen. “And how do I know you don’t want some body parts of your own? You’re in this too.”

Pasha whispered frantically in Somia’s ear.

Somia shook her head. “I don’t trust them.” She looked back at us. “They’ve gone. You can leave.” She feinted with the knife and I slid backwards.

“Be reasonable,” I begged. “Carmen’s out cold.”

“Wake her up,” Somia snapped.

I started to move forwards.

“Not you!” She held me at bay. “Her.” She pointed to Lizzie.

Lizzie started to edge around me, but I touched her shoulder to hold her back.

“It’s OK.” She slid out from under my arm. When she reached Carmen, she placed her fingers on her pulse, sighed with relief, then shook her. “Carmen?”

Carmen groaned.

Lizzie looked at Grady. “She’s burning up!”

“It must be an infection.” Almost in tears, Grady pulled his medical kit from his pack. “She should’ve been taking antibiotics from the start! I didn’t think… Can you get her to take these?” He handed two capsules to Lizzie.

Lizzie sat Carmen up and pushed her matted hair out of her face. “Anyone got water?”

I handed her the bottle from the side of my pack. Somia watched, her knife hand unwavering, as Lizzie wetted Carmen’s forehead and then poured water into her mouth.

Carmen choked and opened her eyes.

Lizzie tucked the capsules into her mouth and poured water after them. “She’s due another painkiller, too,” she reminded us.

Grady nodded and Lizzie gave her the paracetamol she had stashed in her trousers.

“Now go!” Somia barked.

“You’re really going to make us take her out there?” Grady hunched over his pack, glancing nervously up at the stars.

“You can’t stay,” Somia repeated. “Too many people will draw attention here.”

Delirious, Carmen shoved herself away from Lizzie. She crawled out into the open and wobbled to her feet. “We can’t let them win!” She swayed. “Where’s m’knife?”

Lizzie handed it to her.

“I can’t believe she’s still focused on that.” I rubbed my face. “We can’t go for the next checkpoint. We were lucky to get away this time!”

Carmen started to swear at me in Spanish and Will caught her before her legs folded. “Don’t worry,” he soothed. “Ben didn’t mean it. We are going for the next checkpoint.”

“I did mean it!” I snapped. “And no, we’re not!”

Carmen swiped at me with her knife, but missed. Lizzie held her arm.

“All right, Car, we’ll keep going.” Lizzie looked at me. “It won’t hurt to at least check it out.”

I folded my arms. “We should find a place to hole up. Somia’s got the right idea.”

“No!” Carmen howled and Grady clapped his hand over her mouth.

“Stop upsetting her, Ben!”

You are going to bring people here!” Somia cried, furious.

Pasha whimpered.

“Fine.” I ground my teeth. “Give me the map. I’ll show you where the checkpoint is.” I checked the numbers, then tapped my finger on the folded paper. “There. It’s right at the other end of the island near that chapel. We’d have to walk north half the night to get there.” I looked at Lizzie. “Do you want to carry Carmen?”

I will.” Will tightened his arm around Carmen and they both glowered at me.

“I’m not the bad guy here!” I growled.

Lizzie took the map and Will’s torch. “We can go through those trees.” She pointed. “And look – there’s another building and the chapel. Loads of places to hide.”

“Yeah?” I muttered. “Loads of places marked on the map. Places all the other teams will like the look of too. We’ll probably walk right into someone else’s camp.”

“We just have to be careful,” Will said.

“The faster we get to the end of the route, the faster we find help.” Lizzie took my hand.

“If we get to the last checkpoint in the fastest time we could still win.” Grady avoided my eyes as he clipped the straps of his bag over his chest.

“This isn’t about winning any more. It’s about surviving. Haven’t you been paying attention?” I dragged my hand through my hair and reached to pick up my axe.

“We’re not letting them win,” Carmen grunted.

“Yeah, but, Car, what are you willing to risk to stop them?” I exhaled, trying to regain control.

Lizzie held my gaze. “We’re going to take it slowly and be careful. We’ll go from one hiding place to the next and walk without the torches. If we can get ahead of everyone else, we’ll be OK.”

“You think we can overtake the other teams?” I pointed at her ankle.

“They’re still trying to complete the geocaches. We’re not. We just have to get all the coordinates and move on.”

“Wearing our cloaks of invisibility?”

“Don’t be like that, Ben.” Grady stood beside Will and Carmen. “We know how to move quietly, stay low and walk below the horizon.”

I rubbed my eyes and felt Somia watching us. “I’m only trying to protect us.”

“If we can get two more checkpoints completed tonight, while most of the teams are camped out, we’ll be exactly where we planned to be by tomorrow,” Grady said hopefully. “If we only sleep for a couple of hours, then we can stay out in front.”

“You girls decided yet?” Somia sneered.

“I don’t like this.” I pulled out of Lizzie’s grip and walked past them all.

“Don’t have to like it, chico,” Carmen spat. “Just have to do it.”

We needed to walk back across the river mouth – we hiked in silence, our torches unlit.

Grady located the north star and we used it to guide our way. The moonlight cast a faint glow on the scrubland, helping us to keep our footing. The wind bit through my jacket, but the midges and bats were gone. It was too late even for them.

We moved slowly, carefully; once we were over the river mouth, we stayed away from high ground and avoided the cliffs.

Will half-carried Carmen and I supported Lizzie. I could sense unspoken words cutting her lips. She hated silence, always had to fill it, but I was grateful for the quiet. I’d said my piece and been overruled. Now I had to force every step, while my brain screamed at me to go to ground. However carefully, we were going towards danger. I hated it.

“Through the trees, or around them?” Grady’s words shattered the quiet. My heart pounded.

“What do you think, Ben?” Lizzie whispered.

“What do you care?” Resentment sharpened my words and she glanced at me, surprised. Then she looked at Will. “There’s more likely to be teams camping or waiting in the woods, don’t you think?”

Will nodded.

“Then we should go around.” She sounded confident, but I could feel her trembling.

We kept the treeline to our left and moved even more slowly. A campfire glimmered among the trees and I held my breath as we passed it. From Grady’s direction, a stick snapped and we all froze.

“Don’t lift your feet! Push your toecaps along the ground,” Lizzie hissed.

We stood still and listened. Muffled laughter rang through the night. There was no pursuit. We continued with even greater care. Tension wound my muscles to breaking point. What if I fell and drew the other teams to us, like caiman in a swamp?

The campfire faded out of sight. At least there was one team with no night vision. I rubbed my own straining eyes. What had they been thinking?

Slowly we passed the woods and headed back into the open. The sound of water lapping in the night breeze came from the loch on our left and a glow radiated from the broken windows of the building further around the water. A beacon, I thought. Perhaps that’s where all the hunters will converge.

I realized with a shudder that I had been thinking of us as prey for a while now.

To the right, outlined against the midnight-blue sky, the shape of a cross blotted out pinprick stars. I touched Lizzie’s shoulder and pointed. It was the chapel. We were nearly there.

The moorland turned to meadow and long grass tickled our legs, wet in the dampening night. An owl swooped, its wings almost touching my face, then it was gone. I wiped my sweating hands on my trousers.

Finally Lizzie spoke. “I didn’t mean to ignore you, Ben.”

“I know,” I whispered shortly.

“You have to forgive me.” Her voice almost broke. “What if we don’t—”

“We’re not going to die, Lizzie!” I caught her gaze. “Anyway, I’m not angry with you, just afraid we’re walking into trouble.”

Lizzie shuffled forwards. “We have to reach the end,” she said.

“You still think there’ll be help there? The last box had a finger in it.”

“I don’t know what’s going on here,” Lizzie said. “But there will be someone at checkpoint seven–there has to be. We just have to be strong for one more day.” She swallowed. “Twenty-four hours. Less.”

I forced a smile. “When you put it like that.”

She took my hand. “So you’re OK?”

“If you are.” I looked up; we were getting closer to the chapel. “Lizzie… I remembered what you and Carmen were saying when I was … ill.”

“Ah.” She tried to pull her hand away, but I didn’t let her.

“Why didn’t you tell me your dad’s sick?”

Her jaw tightened. “I didn’t mean to hurt you.”

“You haven’t,” I lied. “But how can I be there for you if I don’t know what’s going on?”

For a long time the quiet was broken only by our footsteps. Then she spoke.

“Now you know how I’ve felt our entire lives.”

I caught a breath. “You—”

“I’ve always known there was something going on with you. Even before your dad left, but you never told me. If I tried to ask, you changed the subject until I stopped asking. I figured our relationship just wasn’t like that. We don’t talk about the big stuff.”

“But we do!” I insisted. Then realized my voice had raised. “Don’t we?” I whispered.

“Not really.” Lizzie shook her head. “When your mum was hospitalized that time, I found out from Matt, who heard it from his mum. It’s OK. I found a way to be there for you, just by … being normal. And that’s how you’re there for me. We don’t talk about the bad stuff, we keep it light, and that’s a good thing.”

“Y-you don’t trust me?”

“Of course I do.” Lizzie shrugged. “But I still don’t know what’s going on with you. Maybe one day you’ll tell me, but what I’m trying to say is … if you don’t, that’s fine too.” She leaned against me. “I love you, Ben. You’re my best friend.”

I smiled as my chest ached.

We stopped about a hundred metres from the chapel, behind a crumbling drystone wall. The chapel was as broken as the house we’d sheltered in – one whole side of it caved in, like a sandcastle smashed by a spiteful foot. The moonlight picked out gravestones – weathered, leaning or completely shattered. I thought of the number of houses that had been marked on the map. For only three homes, there were a lot of graves. Generations.

“Is there anyone in there?” Grady said under his breath.

“Impossible to tell.” Will cocked his head. “I can’t hear anything and there’s no firelight, but that could just mean they’re smarter than the team in the house back there … or they’re laying a trap.”

“Is the checkpoint inside?” Lizzie asked.

I shook my head. “It’s behind the chapel. In the graveyard, most probably.”

“A good place for an ambush,” Will pointed out.

“We can still head into the hills and find a cave,” I said, but Carmen turned, her head wobbling on Will’s shoulder like a broken doll. She glared at me and I held up my hand. “All right.” I sighed. “Don’t freak out.” I leaned my axe on the wall. “So, we do what we did last time. Will solves the riddle now, while we’re hidden. We only go for the box when we have the answer.”

“Agreed.” Lizzie pulled out her notebook. “Here, Will.” She dug her calculator from her bag.

“I’ll need more light.”

“It’ll wreck your night vision,” Lizzie warned.

“The moon’s not bright enough for maths,” Will whispered.

Grady got out his torch, but didn’t switch it on. We looked at one another. Then Lizzie pulled a dirty green T-shirt out of her bag and wrapped it around the torch.

“Everyone except Will, cover one eye,” she warned. “You’ll keep your night vision that way.” Then she dragged us into a circle and aimed the light at the ground.

Our bodies shielded the faint green glow. Will crouched under it and held the notebook in one hand, Lizzie’s pencil in the other. He started to write.

“It’s algebra,” he muttered. “A, B, C, D, E. E plus C equals fourteen. D subtract B equals one.” He squinted closer. “Two B minus A equals one. B plus C equals ten.” He chewed the pencil. “A plus B plus D equals sixteen. A plus D plus E equals twenty.” He stopped again. “This isn’t as simple as I’d thought,” he grunted. “I can’t think.”

“Forget algebra.” Anxious, I looked around; still no movement. “Just work through the numbers, yeah? If B plus C is ten, then B has to be a number between one and ten, right?”

“What if some are fractions?” Grady asked. “Or negative numbers?”

“Say they’re not,” I said.

“OK, fine.” Will muttered, chewed the pencil and stabbed at the calculator. “I think I’ve got it,” he said after a few minutes.

“What?” I couldn’t see the paper, it was too dark. Will sat back on his heels. “A, B, C, D, E … seven, four, six, five, eight.”

“It does add up to thirty,” Grady whispered after a moment.

“But it doesn’t give an instruction for the locked box, does it?” Lizzie frowned. “Not like fully rotate clockwise, or wind.”

“Maybe it’ll be clear when we get there,” Grady offered.

“You want to take that risk?” My head was beginning to ache. “What letters do you get if you change the number sequence into the alphabet?”

“Nothing that makes sense.” Lizzie squeezed Carmen’s hand as she shifted restlessly.

“Why aren’t we moving?” she demanded.

“Soon,” Will soothed her.

“Is it an anagram?” I pushed.

“Only one vowel.” Lizzie shook her head. “G, D, F, E, H.”

We all stared, clueless.

“We’re going to have to go and look at the box, aren’t we?” Lizzie whispered.

“Are we all going?” Grady asked. “Only, if it doesn’t need all of us, maybe I should stay here with Carmen.” He spoke in a kind of half-apologetic whisper.

I gaped. “You want us to take the risk while you stay here and hide?”

Grady swallowed. “When you put it like that …”

“I do.”

“I just thought … if we’re spotted by the box, Carmen will slow us down. But if I stay here with her, to keep her safe, then you guys can run away if you have to and … and meet us back here.”

“You’re serious?” My mouth gaped wider. “You want us to lead trouble away from you?”

“He has a point, Ben,” Lizzie said. “It’s what’s best for Carmen and we’re more mobile alone. I’ve got to go because of my thumbprint. I want Will with me… You could stay here, too.”

“Are you kidding?”

“You don’t even want to go for the checkpoints.”

“That doesn’t mean I’m going to leave you on your own. I can’t believe this.” I pushed my fists into my temples as my headache intensified. “Grady is going to stay here, to watch Carmen. You, Will and I are going to the checkpoint. You and Will can open the box while I keep watch.” I rose to a crouch. “We’re leaving our packs here, with Grady, just in case we have to sprint.” I pulled mine from my shoulders with difficulty; it felt welded on, my skin and bone adjusted to the shape of the straps. I dropped it beside Carmen. “Get some more antibiotics in her,” I snapped.

Will stood up and took Grady’s torch. “We might need this.”

Grady nodded. “Good luck.”

I grunted, climbed over the wall and held out a hand to help Lizzie. Will landed beside me, catlike. Although we were heading into a graveyard that could contain an ambush, to open a box that could contain a human body part, it felt good for a moment to be just me, Lizzie and Will, almost like we were in Primary again.

We scurried from grave to grave; Will kept the T-shirt over the torch, moving it over the ground in search of the box and Lizzie clenched her notebook in one hand while she traced her fingers over names and lingered over the impressions of dates. “Sad,” she murmured.

“I can’t see the box,” Will growled. We’d looked around every stone; my head pulsed with each movement I made, my knuckles whitened on the axe.

Lizzie gestured and we ducked behind a large stone that looked as if it might collapse at any moment.

“What do you think? Is it somewhere else?”

“It has to be here,” I said.

Lizzie frowned. “What if we have to dig for it?”

I shook my head. “There’re teams ahead of us. We’d have been tripping over holes all over the place.”

Will was shining the light on one of the graves. “Some of these have stone slabs in front of them. One could lift.”

“But which one?” An aura flickered around my vision. The vision in my left eye blinked in and out. An oncoming migraine. Already I was feeling clumsy and thick-fingered. Unlike myself. I pushed the feeling away. “We can’t lift every stone here.”

Lizzie was staring over my shoulder, reading. “Bessie Tait, Elspeth Tait, Sinnie Tait, Garthe Duncan, Eaner Galdie, Johne Galdie…”

“Say that again?” Will turned like a whip.

“Bessie Tait, Elspeth Tait, Sinnie Tait, Garthe Duncan—”

“That one.” Will stopped her. “Where is it?”

Lizzie pointed. “Just behind you.”

“Any other Duncans?” Will started to crawl towards the grave.

“I…” Lizzie frowned. “Actually, I haven’t seen any. It’s dark, so I might be wrong, but all the rest I found are in family groups: the Taits, the Galdies, the Frasers – Garthe’s all alone.”

Will stopped in front of the grave. There was a stone slab sitting cockeyed on the hard earth.

“Garthe Duncan: Farmer, Engineer, Husband,” Lizzie read quietly. “Your love will light my way.”

Finally, I saw what had caught Will’s ear. “G, D, F, E, H,” I said. “It’s the clue.”

Lizzie nodded. “So we try to lift this stone?”

In answer, Will put down the dimmed torch and jammed his fingertips under one corner. I handed the axe to Lizzie and bent to help him. The stone lifted more easily than I had expected.

“We aren’t the first to get here,” I murmured.

We propped the stone against the grave. Beneath it lay the checkpoint box.

“Open it, Lizzie,” Will said.

The clue to the locked-room game had been written on the gravestone: light. Will shone the torch on the screen and the lid popped open. The geocache box inside was wider and shorter than the previous one. “What do you think is in it?” Lizzie whispered, once she had finished copying the engraved coordinates and clue into her notebook.

I swallowed.

“We could open it and find out.” Will stroked the lid. “We don’t have to tell Carmen.”

“I don’t know.” Lizzie shook her head. “We don’t really need to see, do we?”

“Don’t we?” Will asked. “What if it’s a normal geocache this time?”

Lizzie’s eyes brightened as she said, “You think that’s possible?”

Will shrugged. “If the first caches were sabotaged, they might have given up changing them by this point.”

“We can only be certain if we’re first to reach one,” I pointed out.

“It’s about the right size for a compass again.” Lizzie poked the case.

I looked at Will, but said nothing as he picked up the box. He handed the torch to Lizzie and opened the latch. Although I didn’t want to, something made me lean close.