Neridia could barely comprehend what she was seeing.

The broken grandeur of the ruins had been impressive enough. But this…this was no ruin.

A broad, stepped mountain rose from the rolling sea floor. Thousands of white buildings clustered on the wide tiers, gleaming like pearl in the shifting sunbeams filtering down from the half-seen surface far above. Elegant arches connected one level to the next, so light and airy that it hardly seemed possible that they could support their own weight.

It was like some impossibly huge, intricate wedding cake. Vast, glimmering bubbles of air encased some parts in crystal domes, but many of the towering buildings and elegant, spiraling roads lay open to the ocean.

And, through the sunken city, the sea dragons swam.

At this distance, they were as tiny as minnows, but there was no mistaking those sinuous forms. They soared around the towers and ziggurats as easily as birds through the sky. She could see the luminescent glow of the males, winking like fireflies through the white spires. There were the darker shapes of females too, and others that were too small to be sea dragons, too big to be mere fish.

Home, whispered her strange inner voice. We are home.

Neridia felt like she could stare for a week, and still barely take in a tenth of the city’s wonders. Wide, curving streets opening out into column-lined plazas. Vast statues of dragons, ten times life size, carved into the living rock itself. A huge palace of soaring towers at the very top of the mountain, crowning the city with the unmistakable gleam of pure gold.

And she was supposed to rule it all.

The thought punctured her awestruck wonder as ruthlessly as a sword-thrust. The idea of an ordinary human—of her—put in charge of all this shining splendor was so ridiculous that Neridia didn’t know whether to laugh or cry.

“I can’t do this,” she whispered, alone in her tiny bubble of air. “This is madness. I want to go home.”

This is home, insisted her inner voice. This is our domain. Claim it!

Neridia shut her eyes tight, trying to shut out the city, to shut out that terrifyingly fearless voice. What was she thinking? What place was there for her in this magical underwater world?

*My mate?* John’s mind brushed against hers as gently as a caress.

She opened her eyes to find him hanging in the water at her side, his luminous blue eyes anxiously studying her expression. Here in his natural element, he seemed even bigger than he did on land. The glowing spirals running down his scaled flanks emphasized his powerful bulk. Every slight movement of his finned tail, every idle flex of his ivory talons revealed his strength.

He belonged here. She didn’t.

But she had come too far to turn back now.

She took a deep breath of the stale air, straightening her spine. *I’m okay.* It still felt weird to just think the words, and know that he heard them in his own head. *I was just…it’s all just a bit overwhelming.*

His own mental tone lacked its usual deep, certain ring. *Perhaps I should not have sprung it on you all at once, without preparation. But I thought the sight would delight you more if it came unexpected.*

Underneath Neridia’s thighs, John’s sister heaved a deep, heartfelt sigh. *Please forgive my brother,* the sea dragon said privately, mind-to-mind. *He means well. But you have to remember, this is the male who once put a live and extremely angry vampire squid in my bed, because I idly remarked at dinner that nothing exciting had happened that day.*

Despite herself, Neridia had to smile. *I am really looking forward to hearing those stories you mentioned.*

*Then by all means, let us get to Atlantis as swiftly as possible.* John’s sister broadened the mental conversation to include John. *Brother? Is it safe for us to proceed?*

John swung his horned head to scan the surroundings. Neridia didn’t know how he could see anything in the murky depths, but after a moment he hummed in evident satisfaction.

*The way ahead lies clear.* Flicking his tail, he soared effortlessly up, leading the way. *We will enter by the-*

He broke off abruptly, his head snapping round as if he’d heard something. Underneath Neridia, every muscle in his sister’s back went tense. Both sea dragons stared back the way they’d came.

*What is it?* Neridia turned to look back herself, but couldn’t see anything in the dim light. *What’s wrong?*

*Go!* John swirled back, every talon bared to the full extent as he stationed himself behind his sister. *Get her to Atlantis! Now!*

Neridia jolted back, nearly sliding out of her bubble of air as John’s sister surged forward. She’d thought they had been swimming quickly enough before, but now it became obvious that they had been going at the sea dragon equivalent of a leisurely walking pace. She grabbed at the dragon’s trailing mane, clinging on for dear life.

“What’s going on?” she yelled.

*One of the border guards just spoke to a comrade,* John’s sister responded, even though she’d forgotten to use mind speech. *Wondering why the Master Shark is in such a hurry to reach Atlantis.*

*What? They let him through?* Neridia’s pulse spiked with fear. *Why didn’t they challenge him?*

*Because he is the Master Shark!* The sea dragon’s head wove through the water like a snake as she increased her speed still further. *And since the Knight-Commander hasn’t seen fit to warn his knights about your existence, let alone that the Lord of Sharks is after you, they have no reason to deny him entry! And now he is here!*

Neridia twisted, straining her eyes to try to see through the deep blue sea. John wasn’t following. He’d spiraled up to hang halfway between the sea floor and the surface, facing away from them, his intricate markings blazing as bright as neon signs.

He was so huge, so fierce, that some of Neridia’s panic eased at the sight. He was a sea dragon, a sea dragon Knight, born and trained for battle. He was armored in plated scales, and armed with teeth and claws and powerful magic. Surely no shark, not even the biggest great white, could get past him.

Then she looked past John’s glowing form, and saw what he faced.

The Master Shark wasn’t a great white shark. He could have swallowed a great white whole, in a single mouthful, without pausing.

In a flash, she understood the reason for the Master Shark’s oddly-proportioned face in human form, with its prominent brow ridges and heavy jaw. It was a face from prehistoric times, echoing his true form. No wonder John had been so certain he had to be commanding the plesiosaur shifter assassins. Like them, he was a primitive throwback, a relic from another age.

An age of giants.

“Megalodon,” Neridia breathed.

The biggest shark ever to swim the sea. Eighty feet of muscle and teeth and bottomless hunger.

And John hung motionless, right in his path.

Hands numb with shock, Neridia tugged at John’s sister’s mane to get her attention. *John isn’t following us! He’s planning to fight!*

*What? Of course he’s not-* The sea dragon’s mental voice cut off as she glanced over her shoulder. *What in the-BROTHER!*

Faintly, Neridia heard John sing something back in return. His sister hissed something that was very definitely a dragon swearword.

*What did he say?* Neridia asked, though she was pretty sure she knew the answer.

*That he would cover our retreat,* the sea dragon said grimly, swirling to a halt in the water.

Neridia shrieked as the sea dragon started fluking back toward her brother and the rapidly-approaching Master Shark at top speed. *What are you doing?*

*I’ll be dry-beached before I let my little brother hurl himself down the Master Shark’s gullet just to slow him down!* The sea dragon’s teeth bared in a snarl. *You’re meant to be the Empress-in-Waiting, so act like it! If anyone can stop the Master Shark, it’s you!*

*Me?* Every muscle in her body was rigid with fear. *What do you expect me to be able to do?*

John’s sister didn’t get a chance to answer. Ahead of them, John himself spun around, the luminescent lines on his body blazing with fury.

*GET BACK!* His roar knocked his sister head-over-tail backward in the water. *I told you to get her into the city!*

The Master Shark hurtled toward them, growing larger every second. He was further away than Neridia had thought. She’d been deceived into thinking that he was nearly on top of them, just from how big he already looked.

Which meant…he was actually even bigger.

*Please, John!* Neridia pulled on the mate bond, desperate to get him to listen. *Not even you can fight that thing!*

His sister paddled upright again, matching John glare for glare. *I’m not leaving you. If you want to get your mate to safety, then you’re going to have to come too!*

John snarled, but turned. To Neridia’s relief, he started to swim, herding his sister before him.

Neridia flattened against John’s sister’s neck. The sea dragon’s tail lashed through the water, fighting the drag of the dwindling air bubble. It was clear that she was tiring.

Neridia risked a backward glance. The Master Shark was catching up. His streamlined body was even more perfectly adapted for this environment than the sea dragons. He was close enough now that she could see his tiny, flat eyes. His jaws gaped wide enough to swallow the whole world.

*Swim!* John’s teeth snapped at his sister’s trailing fin. *For the sake of all the sea, SWIM!*

“JOHN!” Neridia shrieked as his fluid body doubled back on itself.

John flashed toward the Master Shark like a bolt of electric blue lightning, claws outstretched. The shark’s triangular teeth clashed together like a portcullis descending, but John darted out of reach just in time. Fast as a snake, he whipped round, seeking to entangle the shark in his coils.

The Master Shark bucked like a bull trying to shake off a rider. John might match him in length, but the shark was at least five times his own mass. Even though the dragon clung on with every tooth and claw, he couldn’t keep a secure grip on the writhing monster. His coiling tail slipped, coming within range of the shark’s twisting mouth.

“No!” Neridia cried out, as the Master Shark’s teeth cracked through John’s scales, sinking deep into his flesh.

With a jerk, the shark flung the sea dragon aside. Without hesitation, John twisted round. Blood trailing behind him in a dark cloud, he threw himself straight into the shark’s path again.

Her mate was going to get ripped to shreds.

*Don’t!* Neridia aimed the thought at the Master Shark like a torpedo. *Please, stop! I’ll surrender, I’ll come with you, just don’t hurt him!*

She had an odd sensation of her mental plea bouncing back unheard, as if she’d shouted at a brick wall. The shark didn’t give any hint that he was even aware of her attempt to communicate. The sea dragon and the shark closed with each other again, and the sea turning red around them.

*Do something, Neridia!* John’s sister pleaded. Despite her brother’s command, she’d slowed again, clearly reluctant to leave him. *Fling him away on a tidal wave, command a whirlpool to swallow him, freeze the very blood in his veins! If you’re the Empress, you have the power!*

“I don’t, I’m not, I’m not!”

John tumbled out of the swirling cloud of blood again. This time, it took him a moment to right himself, his previously-fluid movements stiffened by pain. There were deep puncture wounds in his side, and one side of his tail-fin had been shredded. But despite his wounds, his scales glowed brighter than ever.

He wasn’t going to give up. He’d fight for her to the last drop of blood in his body.

Neridia reached for him, praying to draw that indomitable will into her own frail soul. John’s head jerked round, his eyes widening in surprise. She felt him reach back in return. Their souls met, joined, like clasping hands.

The mate bond blazed up between them, bright and fierce as John’s markings. Neridia shook as if she’d stuck her fingers in an electric socket. She’d thought to draw strength from him…but instead he seemed to be taking it from her.

She knew how his pain was suddenly washed away, his strained muscles moving freely once more. She knew how the touch of her soul filled him with renewed resolve.

*My mate,* his voice whispered in her mind. And then, more strongly, *My mate!*

He swirled to face the Master Shark head-on, his great chest swelling. The shark lunged for him, maw gaping, but John didn’t move.

Instead, opening his own jaws wide, he sang.

Neridia clapped her hands over her ears, deafened by the power of his voice. The music exploded outward like a shockwave, tumbling even the Master Shark’s massive bulk backward in the water.

Neridia didn’t understand the thundering melody, but in her soul she knew what John was saying:

This is my mate, mine, mine alone! You shall not take her!

The Master Shark was beaten back by the tearing maelstrom of notes. Every muscle in John’s body was taut with effort of his song. Slowly, as if battling against some vast weight, he raised his front feet. His claws spread wide.

The sea parted.

At John’s command, a deep chasm sliced through the ocean. From surface to sea bed, the water drew back, trapping the Master Shark on the opposite side of a dry, widening canyon.

Neridia trembled, and felt the sea dragon beneath her tremble as well. Half-seen across that impossible chasm of air, the Master Shark was just a dim, wavering silhouette.

Then the megalodon turned, and was gone.