Chapter 75

Nereus shook his head. "My journey ends here. I've prepared for this day." He swam to the center of his library and raised his hands. The maps on the walls brightened. "Go! I'll hold it back as long as I can."

As they swam toward the exit, Sophia looked back. Nereus stood surrounded by swirling light from his maps, his face peaceful despite the darkness seeping into his cave.

Outside, they could see an enormous shadow moving through the water toward them. Its purple eyes gleamed with hunger.

"This way!" Arin called, leading them up through a narrow crevice.

They shot through the water, the tablet and keystones lighting their path. Behind them, a massive explosion of light erupted from Nereus's cave, temporarily pushing back the darkness.

When they finally stopped, miles away and closer to the surface, Sophia clutched the tablet with shaking hands.

"He sacrificed himself for us," she whispered.

Tharros's face was grim. "He won't be the last."

Kael examined the tablet. "The Everglow Lighthouse is three days' journey from here."

"And the Leviathan will be right behind us," Arin added quietly.

Sophia looked at each of her companions-Tharros with his fierce protective stance, Kael with his newly discovered royal heritage glowing on his skin, and Arin with her worried eyes but determined expression. They had already lost so much, and their journey was just beginning.

"Then we'd better hurry," Sophia said, her voice stronger now. She held up the tablet, which gleamed with the location of the third keystone. "The lighthouse is waiting."

As if responding to her words, both keystones flashed brightly, illuminating something in the water ahead-a strange current flowing against the natural tide, heading directly toward the northern shore.

"What is that?" Tharros asked, eyes narrowed.

Arin's face paled. "A current that flows backward? That's impossible unless..."

"Unless what?" Kael demanded.

"Unless something powerful is already at the lighthouse," Arin whispered. "Something that's calling to the keystones."

The tablet in Sophia's hands suddenly grew hot, and a new mark appeared on the map-a symbol none of them recognized.

"I don't think we're the only ones looking for the keystones anymore," Sophia said quietly, as the dark water behind them seemed to pulse with malevolent purpose.

Convergence Point

Three days of hard swimming had left them exhausted. The Everglow Lighthouse had been both a blessing and a disaster. They'd found the third keystone hidden in its ancient foundation, but the battle that followed had forced them to split up.

Now, a week later, Sophia stood alone on the shore of a tiny, unmarked island, clutching her keystone to her chest. The wind whipped her hair as she scanned the horizon. According to their emergency plan, this was where they would meet if separated. The island appeared on no maps, hidden by ancient magic that bent light around it, making it invisible to passing ships and aircraft.

"Where are you?" she whispered, the fear in her stomach growing heavier with each passing hour.

A splash from the water made her spin around. Relief flooded through her as Arin emerged from the waves, her silver-blue hair plastered to her face.

"Sophia!" Arin rushed forward, embracing her. "You made it!"

"Barely," Sophia admitted, holding up her keystone. "This thing pulled me through a storm I thought would drown me."

Arin nodded grimly. "The keystones protect their carriers. But the protection comes at a cost."

She held up her hand, revealing angry red marks where her own keystone-the one they'd found beneath the lighthouse-had burned patterns into her palm.

"Did you see any sign of the others?" Sophia asked, her voice tight with worry.

Arin shook her head. "Nothing. But Tharros is strong, and Kael-"

"Is right here," came a familiar voice from behind them.

They turned to see Kael emerging from the tree line, his clothes torn and his face scratched, but very much alive. The royal markings on his skin pulsed with silver light as he approached.

Sophia ran to him, throwing her arms around his neck. "I thought we'd lost you!"

Kael held her tight, his heart racing against hers. "Never. I promised, remember?"

As they separated, Sophia noticed he was carrying something wrapped in seaweed-a fourth keystone, glowing with golden light.

"You found another one?" Arin asked in amazement.

Kael nodded. "After we were separated, my keystone pulled me east. I followed it to an underwater graveyard-old ships from a forgotten war. The keystone was hidden in the captain's quarters of the largest wreck, guarded by spirits that..." He hesitated. "Let's just say they weren't friendly."

"That makes four," Sophia said, counting. "Mine, yours, Arin's, and the new one."

A shadow fell over them. They looked up to see Tharros descending from the sky in his dragon form, his scales gleaming in the sunlight. He landed with a thud that shook the beach, then transformed into his human shape.

"You're late," Kael said with a small smile.

Tharros glared at him, but there was relief in his eyes. "I had to take a detour." He reached into a pouch at his waist and pulled out a scroll bound with coral string. "The Shark Clans are mobilizing. They know what we're doing."

"Did they follow you?" Arin asked, instantly alert.

"No. But others might have." Tharros looked at each of them in turn. "The Leviathan's agents are everywhere now. Shadow creatures that can take any form."

Sophia shivered, remembering the shadow version of herself they'd encountered. "We need to work quickly, then."

They gathered in the center of the beach, forming a circle. Each placed their keystone in front of them on the sand-Sophia's silver one, Kael's blue crystal, Arin's green stone from the lighthouse, and the golden one Kael had recovered from the shipwreck.

"What now?" Tharros asked. "Do we just... bring them together?"

"The tablet said nothing about this part," Sophia admitted, looking at the scholar's map they'd received. "It only showed us where to find them."

Kael studied the keystones thoughtfully. "The royal markings on my skin react to my keystone. Maybe..." He reached out, touching his crystal. The markings on his arm flared brightly.

"Try touching them all," Arin suggested.

Kael nodded and placed his hands on all four keystones at once. Immediately, the royal markings spread from his arms across his face and chest, glowing with intense light. The keystones responded, each pulsing in rhythm with his heartbeat.

"They're connecting," Sophia whispered in awe.

The four keystones rose into the air, hovering a few feet above the sand. Slowly, they began to orbit around each other, moving faster and faster until they formed a circle of light. From this circle, a beam shot upward into the sky, then spread outward like an umbrella of light.

Within this dome of light, a three-dimensional map appeared-oceans, continents, and depths all rendered in glowing detail.

"It's a map of both worlds," Arin said, her eyes wide. "The surface and what lies beneath."

The map zoomed in on a particular section of ocean, revealing a massive trench that none of them recognized. At the bottom of this trench, a city glimmered-spires and domes and streets, all preserved as if frozen in time.

"Lumaria," Kael breathed, his voice filled with wonder. "The ancient capital, lost after the Division."

The map shifted again, highlighting three points of light scattered across the ocean.

"The final three keystones," Tharros said, leaning closer.

The first point appeared in a familiar location-the royal palace of Aquaria. The second shimmered deep within what appeared to be a volcanic vent, glowing with heat and danger.

The third, however, appeared in the strangest location of all-it existed as a pulsing light that flickered between their underwater world and the surface world, never fully in either.

"A keystone between worlds," Sophia murmured. "How is that possible?"

As they watched, the map zoomed out again, showing a timeline. Dark tendrils began spreading from the deepest trenches, consuming the light of both worlds. Then, a point of convergence appeared-a place where all seven keystones could be brought together.

"That's it," Arin said excitedly. "The point of convergence where we can repair the Division!"

But even as she spoke, the map changed again. The same convergence point glowed red, and instead of repairing the Division, it showed both worlds colliding, shattering into fragments as the Leviathan grew to enormous size, feeding on the chaos.

"Two possible futures," Kael said grimly. "Depending on our intentions."

The map faded, and the keystones drifted back down to the sand, their light dimming. As they touched the ground, a tremor ran through the island.

"What was that?" Sophia asked, steadying herself against Kael.

Another tremor, stronger this time. The sand beneath their feet began to shift and sink.

"We need to move!" Tharros shouted, grabbing two of the keystones. "Now!"

As they scrambled to collect the remaining keystones, the center of the beach collapsed, revealing a massive sinkhole. From within the darkness, purple eyes gleamed-dozens of them, blinking up at the group.

"It found us," Arin gasped, clutching her keystone tightly.

Tentacles of shadow shot from the pit, grasping for them. Kael slashed at one with his blade, which now glowed with the same light as his royal markings.

"Split up again!" he yelled over the roar that emerged from the pit. "We know where the other keystones are now. Meet at Lumaria!"

"But no one knows how to find Lumaria!" Sophia protested, dodging a shadow that tried to wrap around her ankle.

"The keystones will guide us," Tharros said, transforming partway to give his arms scale armor as he fought back the shadows. "They've shown us this much."

Arin raised her hands, creating a blinding flash of light that temporarily drove back the shadows. "Sophia, go with Kael to the palace. Tharros and I will find the one in the volcanic vent."

"And the keystone between worlds?" Sophia asked, even as Kael pulled her toward the edge of the island.

"We'll figure that out when we have the others," Tharros growled. "Now go!"

As they separated, racing away from the collapsing island, Sophia looked back one last time. The entire island was sinking now, dragged down by whatever creature had been hiding beneath it all along.

"You think it was waiting for us?" she asked Kael as they dove into the ocean.

"I think it wanted us to find the map," he replied grimly. "It's using us to locate the keystones."

Sophia clutched her keystone tighter, feeling its warmth against her skin. "Then we're doing exactly what it wants."

Kael's eyes met hers, determination burning in their silver depths. "Only until we find a way to change the game."

Together they swam deeper, leaving the sinking island behind. Ahead lay Aquaria's royal palace, the fifth keystone, and a growing sense that time was running out. Behind them, the water darkened with shadows that seemed to whisper with the voice of the Leviathan.

"Come, little keys," it seemed to say. "Show me the way home."

The Key Between Worlds

Sophia and Kael swam through the dark waters, following the pull of their keystones. Behind them, the unmarked island sank deeper, swallowed by shadows and hungry purple eyes.

"Do you think Arin and Tharros made it out?" Sophia asked, her voice tight with worry.

Kael squeezed her hand. "They're strong. Arin's magic and Tharros's dragon form... they'll be fine."

But his eyes held doubt that matched her own. The shadow creature beneath the island had been massive-perhaps even a piece of the Leviathan itself.

After hours of swimming, they reached the glittering outer reefs that protected Aquaria's royal palace. Guards with spears made of crystal patrolled the borders, their faces alert and suspicious.

"Halt!" The lead guard raised his weapon when he spotted them. Then his eyes widened. "Prince Kael! You've returned!"

Kael nodded. "We need to see the Queen immediately."

"The palace is on lockdown," the guard said, swimming closer. "Shadow creatures have been spotted in the outer districts. The Queen ordered-"

"Tell her we have four keystones," Sophia interrupted, holding hers up. The silver stone pulsed with light.

The guard's eyes grew even wider. "Follow me."

They swam through hidden passages beneath the coral, avoiding the main thoroughfares where ordinary citizens might see them. The palace shimmered ahead, its spires reaching toward the surface world.

"The fifth keystone is here somewhere," Sophia whispered, feeling the pull growing stronger.

Inside the palace, they found Queen Maris waiting in the war room, surrounded by maps and anxious advisors.

"My son," she said, embracing Kael. Her eyes, the same silver as his, turned to Sophia. "And the human who is not just human."

Sophia bowed her head. "Your Majesty."

"You've brought the keystones," the Queen said, eyeing the glowing objects they carried.

"Four of them," Kael confirmed. "And we believe the fifth is here, in the palace."

The Queen's face grew serious. "The ancient texts speak of a royal keystone, passed down through generations of rulers. I always thought it was just a symbol of power, not a real object with magic."

She led them to a small room behind the throne. Inside stood a pedestal carved from coral and pearl. Atop it rested a crown-simple yet beautiful, made of silver and adorned with tiny crystals.

"The Crown of the First Queen," Maris explained. "No ruler has worn it since the Division."

As they approached, their keystones began to pulse faster, glowing brighter.

"It's here," Sophia breathed. "The keystone is part of the crown."

Kael reached out hesitantly. "Mother, may I?"

Queen Maris nodded, her expression torn between duty and fear.

As Kael's fingers touched the crown, the central crystal detached itself, hovering in the air. The royal markings on his skin flared with silver light that matched the glow of the crystal.

"The fifth keystone," he said in awe, as it settled into his palm.

Suddenly, the palace shook. Guards rushed in, their faces panicked.

"Your Majesty! Shadow creatures have breached the outer defenses!"

Maris turned to Sophia and Kael. "You must go. If the Leviathan's forces get the keystones-"

"We can't leave you!" Kael protested.

"I am Queen," Maris said firmly. "My place is with my people. Yours is to finish this mission." She touched his face gently. "I always knew the markings chose you for a reason."

Another tremor rocked the palace. Through the windows, Sophia could see dark shapes moving through the water, extinguishing the bioluminescent lights as they passed.

"We need to find Arin and Tharros," Sophia said, clutching Kael's arm. "And the sixth keystone."

"The volcanic vent," Kael nodded. "But what about the seventh? The one between worlds?"

Queen Maris's eyes widened. "Between worlds? The legends speak of such a keystone-neither of the depths nor of the surface, but existing in the boundary between."

"How do we find something that isn't fully in either world?" Sophia asked.

Before the Queen could answer, the palace shook again, harder this time. The walls cracked, and water rushed in from a new direction.

"Go now!" Maris ordered, pushing them toward a hidden passage. "Take the royal tunnels-they'll lead you safely out of the city."

Kael embraced his mother one last time. "We'll come back."

"I know," she whispered.

They swam through the narrow tunnel, the five keystones now secured in a special pouch Maris had given them. Behind them, they heard shouts and the clash of weapons.

As they emerged from the tunnel into open water, Sophia gasped. The beautiful city of Aquaria was under attack. Shadow creatures slithered between buildings, their purple eyes gleaming. Citizens fled in panic while guards fought bravely.

"We have to help them," Sophia said, starting to turn back.

Kael caught her arm. "We can't. Not now. The best way to help is to find the remaining keystones."

Tears mixed with the salt water around Sophia's face. "I hate this. Running while others fight."

"Sometimes the bravest thing is to keep going," Kael said, his voice breaking.

They swam away from the city, following the pull of the keystones. The volcanic vent lay to the south, near the boundary of the Shark Clans' territory.

"Do you think Arin and Tharros made it there?" Sophia asked.

"I hope so," Kael replied. "But I'm worried about-"

His words cut off as a shadow passed over them. They looked up to see a massive shape blocking the light from above.

"Tharros?" Sophia called hopefully.

But the shape that descended was not their dragon friend. It was larger, darker, with glowing purple eyes that matched the creatures attacking Aquaria.

"Shadow dragon," Kael whispered in horror.

The creature opened its mouth, revealing rows of teeth that seemed to absorb light rather than reflect it.

"Little keys," it hissed in a voice that sounded like bubbles rising through mud. "The master seeks what you carry."

Kael pushed Sophia behind him, drawing his blade. "Run. I'll hold it off."

"I'm not leaving you," Sophia insisted, readying her own powers.

The shadow dragon circled them, its tail creating currents that pulled them closer.

"The seventh keystone," it said, its voice slipping directly into their minds. "The one between worlds. Do you not see it yet?"

Sophia frowned. "What are you talking about?"

The dragon's laugh sent chills through the water. "The Leviathan knows what you do not. Why do you think you were drawn to this quest, surface-dweller?"

A terrible thought formed in Sophia's mind. She looked down at her hands, at the faint shimmer of scales that had appeared on her skin since she first entered this underwater world.

"No," she whispered.

The shadow dragon dove toward them, jaws open wide.

Kael slashed with his blade, cutting through shadow that reformed instantly. Sophia summoned her power, creating a blast of superheated water that pushed the creature back momentarily.

"We can't beat it," Kael shouted. "We need to run!"

They swam down, using the darkness of the depths to hide. The shadow dragon roared in frustration, its voice shaking the water around them.

"You cannot escape what you are," it called after them. "The seventh keystone has always been with you, Sophia. You are the key between worlds!"

As they fled deeper into the dark waters, Sophia's mind raced with the creature's words. Could it be true? Was she somehow the final keystone?

And if she was, what did that mean for the future of both worlds-and for her own destiny?

In the distance, the volcanic vent glowed with fiery light, offering a beacon of hope. But Sophia couldn't shake the feeling that they were swimming straight into the Leviathan's trap.

"Kael," she said, her voice barely audible, "what if I'm the seventh keystone?"

His eyes met hers, fear and determination mixing in their silver depths.

"Then," he said, "we've just become the most dangerous people in both worlds."

Behind them, the shadow of the dragon grew larger, and ahead, the volcanic vent pulsed with ominous power.

The Sunken Throne

The volcanic vent loomed before them, angry red light pulsing from deep within the earth. Sophia and Kael hovered at its edge, their faces illuminated by the eerie glow.

"Do you think they made it?" Sophia asked, scanning the area for any sign of their friends.

Kael pointed to a series of marks carved into a nearby rock. "Tharros's claw marks. They were here."

Relief washed over Sophia, but it was short-lived. The shadow dragon's words still echoed in her mind: You are the key between worlds.

"We need to find them," she said, pushing the troubling thought aside. "The map showed the sixth keystone is inside the vent, but-"

A familiar roar cut through the water. They turned to see Tharros speeding toward them, his dragon form sleek and powerful. Behind him, Arin's blue-silver hair streamed like a banner.

"You're alive!" Sophia cried as they approached.

Tharros transformed into his human shape, his eyes wild with excitement. "We found it! The sixth keystone!"

Arin held up a ruby-red crystal that pulsed with the same rhythm as their other keystones. "It was guarded by fire spirits in the heart of the vent," she explained, her arms showing fresh burns that were slowly healing beneath her magic.

"We have the fifth one," Kael said, showing them the royal crystal from the palace crown. His face darkened. "But Aquaria is under attack. Shadow creatures everywhere."

Tharros nodded grimly. "They're following the keystones. Tracking our movements."

"The map showed the final location," Arin reminded them. "Lumaria. The lost capital."

"The trench," Sophia said, remembering the deep, dark line on the map. "But how do we find a city that's been hidden for centuries?"

Kael held up his keystone. The royal markings on his skin pulsed in sync with it. "I think... I think I can feel it. Like it's calling to me."

Tharros looked at him curiously. "The royal markings. They're stronger now."