The water was so cold it stole her breath.
Sera plunged into the black pool, the shock of the icy water hitting her like a punch. For a second, she couldn't move. She couldn't think. Then her Tidecaller instincts kicked in.
Her lungs relaxed. The water felt less like an enemy and more like a second skin. She could see in the dark water, not with her eyes, but with her magic. The pool was deep, much deeper than it looked from above. It wasn't just a pool it was a tunnel, leading down.
She could hear Theron shouting from above, his voice muffled by the water.
She didn't wait. She swam down, following the tunnel as it curved and twisted through the rock. Her heart was still pounding, but now it was with purpose, not just fear.
Lila had said to look for the heart of the cave. Where the water was still, but the magic was strong.
Sera swam deeper. The tunnel walls were smooth, worn by centuries of water. Strange, glowing moss grew in patches, giving off a soft blue light. It was beautiful and eerie.
She didn't know how long she swam. Time felt different underwater. Her body was tired from the long day, from the fear, from the crying, but she pushed on.
Finally, the tunnel opened up into another cavern. This one was huge. The ceiling was so high she couldn't see it in the dark water. The floor was covered in white sand that glowed faintly. And in the very center of the cavern, stood a stone pedestal.
On the pedestal was a box.
It was made of a pearly, iridescent material that looked like mother-of-pearl. It glowed with a soft, silver light, just like Lila's ghost had. And around it, the water was perfectly, unnaturally still.
The heart of the cave.
Sera swam toward the pedestal. As she got closer, she could feel the magic pulsing from the box. It was old magic. Powerful. Sad.
This was it. The key. The thing Garrett wanted. The thing that could break the Deep Sovereign's barriers or break the King's curse.
She reached out a trembling hand.
Before she could touch it, a voice echoed through the water. Not Lila's voice. A deeper, colder voice.
"Stop."
Sera jerked her hand back and spun around.
King Kadrin stood at the edge of the cavern. He wasn't swimming. He was standing on the sand, the water parting around him like he was in a bubble of air. His silver hair floated around his face like a halo. His eyes glowed in the dark water, fixed on her.
He looked… different. Not empty. Not curious. He looked angry.
"What are you doing here?" he asked, his voice clear and sharp even underwater.
Sera's mind raced. How did he find her? How was he here?
"I… I was looking for answers," she said, her own voice sounding strange and bubbly in the water.
"By sneaking out of your room? By meeting spirits in forbidden caves?" He took a step toward her. The water swirled around his feet. "Captain Theron told me everything. He followed you. He heard you talking to your sister's ghost."
Sera's heart sank. Theron had heard. He'd told the King. And now the King thought she was a traitor, a spy.
"It's not what you think," she said quickly. "Lila's ghost is trapped here. She told me about the key. About the curse. About everything."
Kadrin's eyes flicked to the pearly box on the pedestal. For a second, something flashed in his face pain? Recognition? Then it was gone, replaced by cold hardness.
"Thessaly's box," he said softly. "I haven't seen it in three hundred years."
"Thessaly?" Sera asked. "The woman who cursed you?"
Kadrin didn't answer. He walked toward the pedestal, his movements slow, careful. He stopped in front of the box and just looked at it. His expression was unreadable.
"She left it here," he said, more to himself than to Sera. "A parting gift. She said it held the truth. The truth about us. About why she did what she did." He reached out a hand, but stopped just before touching it. "I never opened it. I was too angry. And then… I couldn't feel angry anymore. Or anything."
He turned his glowing eyes back to Sera. "And now you're here. A Tidecaller. A sister to a murdered Tidecaller. Connected to my enemy. And you find the box on your first night in the palace. Do you expect me to believe that's a coincidence?"
Sera shook her head. "No. It's not a coincidence. It's because of Lila. She led me here. She wants me to help."
"Help who?" Kadrin asked, his voice sharp. "Me? Or the Deep Sovereign who wants this box?"
"You," Sera said firmly. "I want justice for my sister. And your enemy is the same as mine."
Kadrin studied her for a long moment. The water around them was so still. So quiet.
"Prove it," he said finally.
"How?"
"Open the box."
Sera stared at him. "What?"
"Open it," Kadrin repeated. "If you're telling the truth, if you're not working for the Deep, then open it. Show me what's inside."
Sera looked at the box. It glowed softly, invitingly. But she was afraid. What if it was a trick? What if opening it did something terrible?
But she didn't have a choice. If she didn't open it, the King would never trust her. And she needed him to trust her. She needed his help to stop Garrett, to find the truth about Lila.
She took a deep breath, reached out, and touched the box.
It was warm. Not cold like stone or metal. Warm, like a living thing.
The lid wasn't locked. It lifted easily.
Inside, there was no key. No treasure. No magical artifact.
There was a letter. A single piece of parchment, folded neatly. And a small, dried moonflower, the kind that only bloomed during the festival.
Sera picked up the letter carefully. The parchment was old, the edges crumbling. The writing was elegant, looping script.
She unfolded it and read aloud, her voice trembling.
"My dearest Kadrin,
If you are reading this, then you have finally come to find the truth. Or someone has found it for you.
I am sorry. More sorry than words can say. I never wanted to hurt you. I loved you. I love you still.
But my father… he is not what you think. He is not a monster. He is a king, like you, trying to protect his people. Your people have been poisoning the deep waters for centuries. Your ships, your magic, your waste it is killing us. My father asked me to stop it. To use our bond to make you see.
But you wouldn't listen. You called me a traitor. You rejected me in front of your whole court. And my father… his grief and anger made him cruel. He cursed you. And he made me help.
The curse was meant to make you understand. To make you feel the emptiness we feel as the deep dies. But it went wrong. It took too much. It took everything.
This box holds the only cure. A memory. The memory of our love. Of the day we met under the moonfall. If you can feel it again, even for a second, the curse will break.
But to feel it, you must forgive me. And I do not deserve your forgiveness.
I am leaving now. Going back to the deep. I will spend the rest of my life trying to fix what my father has broken.
I will always love you.
Yours, even in the depths,
Thessaly."
Sera finished reading. The words hung in the water between them, heavy and sad.
She looked at Kadrin. His face was pale. His eyes were wide. He was staring at the letter like he'd been struck.
"She… she loved me," he whispered. The words sounded strange in his mouth, like he'd forgotten how to say them. "She didn't betray me. She was trying to help."
"The curse was an accident," Sera said softly. "A terrible accident."
Kadrin reached out and took the letter from her. His hands were shaking. He traced the words with a finger, his expression full of a pain so deep it made Sera's heart ache.
"Three hundred years," he said, his voice breaking. "Three hundred years of nothing. Of emptiness. And all because I wouldn't listen. Because I was too proud. Too angry."
He looked at Sera, and for the first time, she saw tears in his eyes. Real tears, mixing with the water around them.
"I can feel it," he whispered. "The pain. The regret. It's… it's awful." He pressed a hand to his chest. "But it's real. It's real."
The curse was breaking. Right in front of her. Because of a letter. Because of a memory. Because of love.
But something was wrong.
The water around them was getting colder. Darker. The glowing moss on the walls was dimming.
And from the tunnel behind them came a sound. A low, bubbling laugh.
Sera turned.
Garrett stood in the tunnel entrance. He wasn't alone. With him were two of his green-eyed friends. And they were all holding glowing green stones that pulsed with dark magic.
"How touching," Garrett said, his voice slick and poisonous. "A love letter from beyond the grave. Too bad it's too late."
He looked at the box on the pedestal, and his eyes lit up with greedy excitement.
"Thessaly's box. The key to the deep. And you led me right to it, Sera. Thank you."
He raised a hand, and the green stones glowed brighter. The water began to churn, pulling Sera and Kadrin toward him.
Kadrin shoved the letter into his pocket and stepped in front of Sera, putting himself between her and Garrett.
"You won't touch her," he said, his voice strong and clear. The tears were gone. Now he just looked like a king. A very, very angry king.
"Or what?" Garrett sneered. "You'll feel at me? You're a broken old man, Kadrin. A hollow king. You can't stop us."
"I am not hollow anymore," Kadrin said. And he raised his own hand.
The water didn't just churn. It obeyed.
It wrapped around Garrett and his friends like ropes, holding them tight. They struggled, green magic flashing, but Kadrin's power was stronger. It was the power of the ocean itself, and he was its king.
"You will leave this palace," Kadrin said, his voice echoing in the cavern. "You will leave my kingdom. And you will never touch Sera Blackwater again."
He clenched his fist.
The water squeezed.
Garrett screamed, a sound of pure rage and pain. Then, in a flash of green light, he and his friends vanished. The green stones fell to the sand, crumbling to dust.
The water stilled.
Sera let out a breath she didn't know she'd been holding. "Is he… gone?"
"For now," Kadrin said, lowering his hand. He looked tired. "But he'll be back. And next time, he'll bring an army."
He turned to Sera. His eyes were still full of pain, but also something else. Something like determination.
"You were right," he said. "About everything. And I was wrong. I'm sorry."
Sera shook her head. "You don't have to apologize."
"Yes, I do," he said. "And I have to do more than that. I have to fix this. All of it." He looked at the empty pedestal. "The box is a key, but not the way Garrett thinks. It's a key to my memories. To my heart. And now that I have it back…" He took a deep breath. "Now I can fight."
He held out a hand to Sera.
"Will you help me?" he asked. "Will you help me stop the Deep Sovereign? Will you help me save this kingdom?"
Sera looked at his hand. At his face, no longer empty, but full of feeling pain, hope, fear, courage.
She thought of Lila. Of justice. Of a world where people like Garrett didn't win.
She took his hand.
"Yes," she said. "I'll help you."
Kadrin nodded, a small, real smile touching his lips. It looked strange on his face, like he was remembering how to do it.
"Then we have work to do," he said. "Starting with getting out of this cave."
But as they turned to go, the ground beneath them shuddered. The walls of the cavern cracked. Sand and stone rained down from the ceiling.
Garrett's last act of spite he'd destabilized the cave. He was trying to bury them alive.
"Run!" Kadrin shouted, pulling Sera toward the tunnel.
They swam as fast as they could, the cave collapsing behind them. Rocks tumbled past them. The water turned cloudy with dust.
Sera's lungs burned. Her arms ached. She wasn't going to make it.
Then a strong arm wrapped around her waist, pulling her forward. Kadrin. He swam with power and purpose, cutting through the water like a knife.
They burst out of the tunnel just as the entrance collapsed behind them, sealing the cave and Thessaly's box forever.
They surfaced in the first cave, the one with the pool. Gasping for air, they pulled themselves onto the stone floor.
Sera lay on her back, breathing hard, staring at the ceiling. She was alive. They were both alive.
She turned her head to look at Kadrin. He was sitting up, water dripping from his hair, looking at the collapsed tunnel with a sad expression.
"The box is gone," he said quietly.
"But the letter isn't," Sera said. "You still have the memory. You still have the truth."
Kadrin looked at her, and his smile came back, a little stronger this time. "Yes. I do."
He stood up and offered her his hand again. "Come. We have a festival to get back to. And a war to plan."
But as they walked toward the cave entrance, a figure stepped out of the shadows, blocking their way.
It was Captain Theron. His sword was drawn. And his eyes were glowing a faint, sickly green.
Sera's blood ran cold. Theron? He was supposed to be loyal to the King. But the green glow in his eyes was unmistakable. He'd been corrupted. Maybe for a long time. He smiled, a cruel, empty smile. "Going somewhere, Your Majesty?" he asked, his voice flat and wrong. "I'm afraid the Deep Sovereign has other plans for you. And for your little Tidecaller pet." He raised his sword. Behind him, more figures emerged from the shadows palace guards, their eyes all glowing the same eerie green. They were surrounded. Outnumbered. And the one person they thought was on their side had just become their greatest enemy.