The cold slices into me. I was right when I thought it would feel as sharp as knife blades. The pain of it makes me lose some of the breath I’m holding, but I fight against the urge to surface. I have to keep swimming deeper.

To my right, on the underside of the iceberg, I see a glowing light coming from a hole that looks like it could be the entrance to the cave. I kick forward, and as I do, I feel something rough and immense brush across my legs.

I whirl around in the water, my spear out in front of me, my lungs burning, and see the shark swimming back and forth in a tight circle. Its flat black eye reminds me of Katla’s deadly gaze. It’s the eye of a killer who feels nothing but their own thirst for death.

My mind flashes back to the visions I had on the beach at home. Of something in the water circling me. Was it a premonition? Does this mean I am about to die?

I look back at the hole. I’m so close. I have to get there before the shark gets to me. It’s watching me, waiting for me to act. I have to move, or I will drown. With a frantic push, I kick fast, stabbing my spear at the huge shark as it surges at me on my left side.

I manage to jab it in the mouth, the deep blackness of its gaping jaws threatening to close down around my arm. I yank back on my spear, and the water around me fills with blood. I don’t know if it is my own or the shark’s, and for a moment I am sure this is the end of me. But then I feel the slippery contours of the opening in the ice, and I reach with my free arm and grab on, pulling myself through. At any moment I expect the shark to bite off my legs, but it doesn’t. I look up and see that I am near the surface. I break through with a gasping, pained breath. I have found the cave at the center of the iceberg.

I hear a voice in my mind. Do not be afraid. Is it Sýr’s? It sounds similar but different somehow. Regardless, it brings me a touch of comfort.

Shivering and weakened by the cold and the fear and the lack of air, I pull myself up onto a smooth lip of ice.

“W-warm,” I chatter. My runes glow, and I clutch myself, willing my body not to freeze solid. My hair hangs in icy ropes around me.

The ice cave is empty, with slick walls that look as though they have been eroded for thousands of years by the seawater. l can’t see well, due to the low light in the cave, but I feel my way along, moving toward the glowing green light that attracted me in the first place.

As I crawl farther in, I imagine I am traveling down a long, deep gullet. The sides of the cave, wet and rippled as they are, will soon close in on me and swallow me forever. I put my hands out in front of me and feel nothing but cold air. The emptiness is overwhelming, and it’s getting hard to breathe. I don’t want to have my sickness here. I might freeze to death. I have to do this fast.

Focus on the light, Runa. That voice again. It must be Sýr’s. It’s so familiar.

I squint as I move forward. The green light in the distance glows brighter and brighter as I advance. Soon I come to a bigger opening in the cave wall. A soothing pale green light flows from the hole, spilling over the shimmering white cave walls and rippled mounds of ice.

“After you,” I joke, my voice weak. “No, after you.”

I take a deep breath. I don’t know what lies beyond the entrance to this glowing chamber, but I know things can’t get much weirder than they already are. Sýr flashes in my mind, then Einar and Oski. I can do this. I have to.

I crouch and crawl through the tunnel headfirst. It takes me to a larger, domed chamber, also white and empty. I walk to the center of the chamber and note its iridescent walls. It’s like being inside a giant shell.

I turn around, admiring the room, and spot a few more small tunnels leading into and out of the domed room. I look for the source of light and see that there is a narrow, chimney-like flue in the top of the dome that goes out the top of the iceberg. Daylight shines through the hole and fills the room. There is also a hole in the bottom of the cave, like a well opening, and it glows with the most beautiful shade of green, like jewels or new spring grass.

I hear a deep growl behind me, and I spin with my spear outstretched.

A small man stands in the cave, naked save for a leather loin cover. He is no ordinary man, though, and I understand at once why Orð has sent me here. The man’s shimmering face is framed by patches of long black hair hanging in shiny sheets like kelp from a rock. His neck has dark slits on the sides, and his hands and feet have wedges of skin webbed between the fingers and toes. I smell the pungent odor of rotting fish and notice that the man’s teeth are pointed like a shark’s and protrude slightly from his mouth. He carries a net full of fish and a spear identical to mine.

“A marbendill!” I gasp. Amma told me of these creatures. She even had a scroll with drawings of one. I never believed they were real. Who would? A marbendill is a kind of half man, half fish. Amma said no one has ever seen a marbendill above the surface of the water. She told me about sailors and fishermen falling into the water only to be terrorized by such creatures beneath the waves.

Like Orð said, they have an intense hatred of mortals. I know enough to be terrified, for marbendills can see a person’s inner emotions, and they can plant ideas and images in the mortal’s mind.

I also remember that marbendills can dive deep, to the ocean floor, and are miners of precious stones. If that’s true, then perhaps this marbendill can help me find some time stones.

The marbendill doesn’t acknowledge my outburst, but stares at me with a scowl on his wide, flat face.

“Where did you get my spear?” he asks at last. His voice sounds like seashells clacking together.

“I found it,” I say with a touch of defiance. I don’t know where this boldness is coming from.

“Give it back,” he says.

“You have another,” I say, pointing to the one he’s carrying. It is the same gleaming white color as the one I carry and is also inlaid with elaborate swirls.

“Give it,” he says again in a low growl, ignoring my reply.

I hesitate. “On one condition—” Suddenly I feel the sensation of something creeping through the edges of my thoughts. A clacking sound.

Give it, give it.

I shake my head and grasp my runes. “OUT!” I shout, forcing the voice from my mind.

The marbendill recoils and then begins to laugh. “Runecaster. What are you doing in my lair?”

He begins to pace back and forth, like he’s getting ready to strike.

“Orð sent me,” I say, keeping my spear out in front of me.

“Orð! That old sea turtle?” The marbendill stops pacing and stares me down. I can feel him trying to wheedle his way into my thoughts again. “Humph,” he grunts when he is unable to gain entry. “Strong runecaster. Stronger than usual.”

“Orð said you could help me,” I say. “That you’re the one.” I don’t have time to be terrified. I need the stones.

The marbendill scoffs. “Orð is not smart. He leaves the beauty and bounty of the great sea to wither away in an old tree. He is the keeper of death. I am the keeper of life.” He widens his arms, gesturing to his cave.

“Imagine,” he continues, “choosing to spend eternity in such a place instead of free in the sea where you can hunt and fish and swim with the great sharks and eat delicious things.”

“Well,” I say, “perhaps he doesn’t like the cold.”

“What?” he shouts. “Not like the cold? Cold gives a long life! Cold can give many lives!” He peers into the green circle between us. “You should learn this.”

I can’t figure out this creature. I don’t know if I will gain his help or not.

“I ask you, runecaster,” he says in his growling tone. “What do you seek?”

“I seek time stones,” I blurt, and the statement hangs between us in the cold air.

“You have one, runecaster,” he says, pointing at my spear.

“Huh?” I raise my spear and examine it.

“Pity,” he says. “Cracked. Useless.”

“This? This is a time stone?” I touch the cracked brown stone on the blunt end of my spear.

“Indeed,” he says. “Was. Now broken.”

“I can’t believe that all along there was a time stone on this thing,” I say.

“Not a thing!” the marbendill shouts.

I step backward, startled by his anger.

He points to my spear. “The great weapon of the horned whale. Carved by my own hands.”

A whale horn? “How did you manage to kill one by yourself?” I ask and then immediately regret it.

The marbendill hurtles his own spear into the wall, where it sticks with a dangerous finality. He steps forward. “I did not kill her. I am Kálfur, Watcher of the Deep. The great horned whale leaves me her weapon as a token of respect when she passes from this life into the next. It was a gift. Now give it back!”

“I’m sorry,” I say. “I found it. And I need it. This spear has saved me more than once. I love it.”

The marbendill, all signs of his rage suddenly gone, regards me with curiosity. After a time he nods. “If you love it, then you keep it,” he says.

“Thank you,” I say. “You are very kind.”

“Bah!” he says, squatting to pull fish from his net and nibble on it. He appears to be eating it raw. He offers me some, but I decline.

“The time stones…?” I begin.

Kálfur throws part of a fish carcass at me. “Time stones, time stones, all you ever say. Every time I see you. Time stones, time stones.”

“Every time?” I ask.

The marbendill grunts and wipes his mouth. He walks over to the green, glowing hole and pulls a long line from his belt. He holds out his hand, palm up. “Come,” he says.

“What?” I ask, edging closer with caution.

“Your rune,” he says. “Give it to me.”

“Why?” I ask. How do I know there are any time stones left? I can’t give this creature one of my runes. “What are you going to do with it?”

“Give it.” He wiggles his fingers.

I sigh and pull a rune from my pouch. It is Nauð, the rune for need. I hold it out. “But if you touch it…” I say, hesitating.

“Give it,” he says again.

I place the wooden piece in his palm, noting how cold and clammy his skin is.

“Are you going to tell me—?” But I have no time to finish, for he drops my rune into the green hole.

“Hey!” I shout. “I need that.”

“No, runecaster,” he says. “We will make more. Another,” he says, holding his hand out again.

“No,” I protest. “I came here to get time stones to make more runes, not lose the ones I have.”

“Yes, yes,” the marbendill says. “You say this each time. You need more runes, time stones, time stones. You need to trust Kálfur.”

“Trust you? You want me to give you my runes so you can dump them in this hole?”

He stares at me. “Yes,” he says.

Looking into his deep green eyes, I know I am not going to be able to reason with him. I don’t know what he means when he says we’ve done this before, and I’m certain he is confused. Still, I remove my pouch from around my neck and dump the remaining runes into my hand.

“Thank you,” I whisper to them. “I’m sorry, but I believe this is what I have to do.”

Shaking, I hand them over to the marbendill.

He takes them, nods at me, and tosses them all into the hole.

“The time stones live in here,” he says, pointing at the green hole. “They demand a trade. You want a stone, you offer a stone. You want a rune, you offer a rune.”

I nod. Finally he’s explaining something. “How do they work?” I ask.

Kálfur shrugs. “Ancient brown water stone holds within it water from the deepest ocean. The first waters. From the time of creation.”

“The first waters?” I ask. Amma never told me about this.

Kálfur looks at me. “You call them back now.”

“Call them? My runes?”

He nods. “Hurry,” he says. “Before they forget.”

“Okay.” I clear my throat. I close my eyes and call out the name of my runes. “Fé, Úr, Þurs, Óss, Reið, Kaun, Hagall, Nauð, Ís, Ár, Sól, Týr, Bjarkan, Maðr, Lögr, Ýr.”

The green hole emits a bubbling noise and then small brown pebbles start popping out onto the smooth cave floor between us.

The marbendill motions for me to pick them up.

I gather them. They look like simple stones and nothing more.

“These are the runes?” I ask.

“Speak to them,” he says. “They are listening.”

I touch the stones one by one, and as I do, I notice a faint glow as the water within them shimmers. “I call upon you,” I say. “I need your help on my journey.”

The stones begin to rattle in my palm, and the design of each rune appears in glowing relief before fading to look again like common stones.

“A disguise,” I say, delighted.

The marbendill looks at me and grunts. “New runes have memory like water. Hold time like water. Change like water. And they are constant like stone. Strong like stone. You must be both. You must yield and never break. You must move forward and stay here.” The marbendill’s voice seems to grow farther away.

My vision blurs, and the white of the cave becomes a swirl of confusion and fog. No. I thought I was growing beyond these fits. I can’t get lost here. I have to get out to find Sýr. Sýr!

I feel a hand grasp my shoulder, and I spin to see Sýr standing behind me. Her face appears as if underwater, like there is another face floating on top of it. I see a faint smirk flash across her mouth and then disappear again.

“Sýr,” I call. “I’m coming.”

She reaches toward me with her hand, so close we could touch, and as I feel her fingers graze mine, I feel another sensation—a hard blow—across my back.

“Oof!” I grunt, stumbling forward, almost falling face first into the green hole of the cave. When I roll over, the fog has cleared, Sýr is gone, and the marbendill is standing over me, brandishing the blunt end of his spear.

“Are you crazy?” I shriek. “I was trying to get to my sister.” “No,” he says. “Not your sister. The witch. She wants your stones.”

I look down and see that I’ve dropped my new runes. I gather them and put them into my pouch. “I’m sorry,” I say. “I’m so sorry. I won’t drop you again.”

Sitting here in the marbendill’s cave, clutching my runes, I am struck by the eerie sensation that I have been here before. I have done this before. But the icy walls seem as foreign as any place I’ve been.

“I have been here before, as you say.” My voice comes out in a whisper.

“Many times, yes,” he says.

“For the same reason?” I ask. How can this be happening?

“Yes,” he says.

“But I failed?” I ask, afraid of the answer.

“Yes,” he says.

“Why?” I am not sure I want to know.

“You did not trust yourself,” he says.

How am I any different now than I was before? None of this makes sense.

“In my heart I know I will fail again,” I whisper.

“Then I will see you in another turn of the universe,” he says.

I am crying now. “I’m tired,” I say, wiping at my face.

“You fight yourself,” he says. “Very hard to make your journey with a binding spell on your spirit.”

“What? What do you mean?” I ask. What binding spell? How can he see my spirit?

“There is spell keeps you here,” he says. “It keeps you now.”

Stay with me. Stay here. Stay now. Sýr’s voice in my mind. The sleeping spell she would say to me every night. But why would Sýr bind me? She was trying to help me expand my abilities, not limit them. Wasn’t she?

“Take it off,” I say. “The binding spell. Can you?”

“I cannot. I am no runecaster,” he says. “The one who can take it off is the one who placed it there.”

If it was Sýr, then I will never get it off unless I find her.

“I need to find my sister. I need you to tell me what I should do,” I plead.

“You must let me in,” he says.

“In? Where?” I ask.

“Into your mind. I will see what has not happened yet.”

I hesitate. He has helped me with the stones. But can I really trust him? I must. I have to know. “Fine,” I say. “But when I want you to go, you go.”

His eyes grow darker. The pupils dilate, and a thin, filmlike third eyelid retracts so that his eyes protrude from his face.

I recoil from the intensity radiating from his eyes. I have a crawling feeling, like a cold hand is reaching under my skin and grabbing hold of my guts. I can feel the marbendill’s mental grip on me and am powerless to stop the invasion.

“Why me?” I ask. I hear my own voice as if from far away. “I’m not special.”

“No, you’re not,” says the marbendill. “But you have the burning heart of a seeker. That is all you need.”

“I’m scared.”

“Yes, yes,” he says. His voice is soothing. “Don’t be afraid. Everything will work out as it should.”

“Tell me,” I plead. “Tell me how I can save my sister.”

“The answer is always the same. Use the time stones. Enter moonwater. Cast them in the circle. Draw the witch out. Entice her. Her desire for power will be her undoing.”

The marbendill releases my mind, and I am left with a feeling like someone left a door open in my head. It takes me a moment to compose myself.

The marbendill leans closer to me, a grave expression on his face. “If you choose to go through time, you may risk your immortality.”

“What do you mean, go through time?” I ask. “How is that possible?”

“Your soul,” he says, not answering my question. “You might lose it.”

“How?” I ask.

He shakes his head. “It is a risk you take. When you live more lives than you have been given. Same warning I always give.”

Now more than ever I feel like I am not going to come back from this journey alive. But it doesn’t matter. Sýr matters, and the mission. They are more important. I cannot let her die.

“Why are you helping me?” I ask.

“Because you helped me once, a long time ago,” he says.

“I wish I remember,” I say.

“No, you don’t,” he says, turning his back on me.

I thank him, but he does not speak to me again. It’s as if I have ceased to exist.

I leave him, crawl back through the tunnel, and regard the hole that leads to the icy water. I take a big breath and slip through, the cold penetrating me to the core. The huge green shark is still patrolling the waters, and I swim away from it as fast as I can. I reach the edge of the ice floe, use my spear to climb out of the water, and land on the ice like a sputtering, pale fish.

“Runa!” I hear Einar shout. I watch him make his way to me. Suddenly he’s there, draping me in his own cloak. It smells like honey and sweat—and Einar. I shiver and turn back to look at the water. The sharp tip of the green shark’s fin disappears back into the depths.

Einar lifts me up and helps me back across the tipping ice floes to the shore, where he deposits me on solid ground, safe but half-frozen.

“We thought you’d been eaten,” says Oski cheerfully.

“No we didn’t,” Einar says, rubbing my arms through the cloak.

I look at him, my teeth chattering so hard I fear they will crack. “You weren’t worried?”

“I didn’t say that. But I knew you hadn’t been eaten,” he says, continuing to rub the life back into my frozen limbs.

“How?” I ask, leaning into the warmth of him.

“Because I could still feel you,” he says.

“Feel me,” I say. “Is that an elf thing?”

“No,” he says. “It’s a Runa and Einar thing.” He grabs a corner of the cloak and rubs my soaking hair with it. “Now stop talking. You need a fire. And soup. And tea.”

“We have weird tales to tell you, runecaster,” says Oski.

“You have no idea,” I say.