Milius, Sirius, Ariana, Shakil, and Frederick all scattered as the king's fist plunged downwards; it slammed into the floor of the Catacomb, sending debris flying everywhere. Milius, Frederick, and Ariana converged on one side of the room, their shields raised against the falling rocks, with Sirius and Shakil on the other, all gazing up at Phontus in terror as he drew back his fist, preparing to strike again.

“We'll never make it out of here without the dragons!” Ariana said urgently.

Milius’s eyes swiveled onto the still-unconscious steeds as she spoke. The dragons were, as he knew, still alive; it had been explained by the Elders long ago that they were bound to the swords, and could not come to mortal harm so long as the blades were still in tact. But the sudden flood had clearly caused a great deal of damage.

“We have to get them out of the water first,” Milius said.

The words had barely left his mouth when another huge crash sounded from the other side of the room; a plume of smoke was rising upwards through the gap from where Sirius and Shakil had been, but to Milius’s intense relief, both of them emerged from the cloud seconds later, from different sides, though mercifully unscathed.

“Then get rid of the water!” said Sirius, who was swimming towards them.

“Oh, thanks, didn't think of that!” Milius hissed. He looked away from his cousin and up at Phontus, who was trying to squash Shakil. “Oy, Barnacle Beard!” he yelled. Phontus turned his boulder-sized face to Milius, his glossy eyebrows raised.

“I challenge you!” Milius said. A ringing silence followed his words, then Phontus, who had been looking just as stunned as everyone else, laughed so hard that the whole room began to quake again.

“You? Challenge me? To what, exactly? I'm several hundred years old and versed in the most advanced sea magic, boy, you cannot possibly hope to defeat me!”

“If you're so sure, then you should have no trouble at all!” Milius said. “You want to prove that you’re the real king of the sea? Then do it. I challenge you, in the same way you pitted me against your servants in the castle!”

“Milius!” Shakil moaned. “What are you doing?”

But Milius ignored him; he continued to stare up at Phontus, who seemed to be considering. “I am a king,” he said abruptly, “the rightful heir of the throne of the sea. I have the whole underwater realm under my control. What could you, lowly human, possibly offer me, should I emerge victorious in this ‘challenge’?”

“Shakil.”

The word left Milius’s lips promptly, easily, baldly. Shakil looked just as taken aback as Phontus.

“What?”

“You said the Sapphire Knights were your favourites, didn't you?” Milius asked Phontus, ignoring Shakil. “If we win, you let us return to the surface, unharmed. If you win, you get to keep him!”

There was a horrified silence. Ariana and Sirius were staring at Milius, as though they could not believe their eyes. Shakil looked thunderstruck. Frederick looked thoroughly excited.

“Hmm . . .” Phontus said, raising an enormous hand to stroke his beard and looking thoughtful. “They certainly would make nice additions to my collection, the great blue dragon of water and the mystical sword Oceannerva. . . . But I decline.”

“What?”

“You are correct, young one, I would enjoy having him. But why engage in some pointless contest, when I can just take him anyway!” he roared, and his whole body plunged downwards, his meaty arms thrust out towards them. Milius seized his chance.

The Orb of Triton pulsed in his arms as Phontus swooped, and the water in the room responded readily, easily, as it always had before, and as he knew it would now; it gushed upwards, streaming out of the room with so much force that Phontus, taken completely by surprise, was washed out along with it, leaving the room as empty and dry as it had been earlier.

“You were going to barter me?” Shakil demanded incredulously.

“Of course not,” Milius said truthfully. “I just needed him distracted so he'd loosen his control over the water, so I could force it out. And it worked!”

“You could have told me!” Shakil said.

“How?” Milius asked, raising his eyebrows. “Shout it across the room when you were playing with the King?”

“Uh — well . . . fine,” Shakil said, sighing. “Next time.”

“He's coming back!” Ariana screamed suddenly, and sure enough, Phontus’s gigantic form was swimming towards them again.

“Stay with them,” Milius told Ariana, gesturing at the dragons, who were now stirring, albeit rather feebly. “Whatever you can to help them up. Sirius — Shakil.” He gestured towards Phontus and Milius hoisted the Orb, summoning ropes of water that seized them around the waists and flung them into the water above, bubbles blossoming around their heads at once.

“So that's what you did, eh?” Phontus rumbled. “Distract me so you could weaken my hold?” He snorted. “What considerable ingenuity. Too bad it's about to go to waste!”

He burst into motion, waving his huge arms with a flourish. A volley of enormous, jagged ice shards solidified instantly, and with another swipe of his hands they plunged after them with horrifying speed, propelled by the water.

Sirius swam out to intercept them, the blazing Vulcatrix aloft, and he slashed at the first, melting it completely. Several charged right at him, but the rest changed direction, soaring towards Milius and Shakil. Shakil swung at his own oncoming projectiles — but he didn't have nearly as much luck as Sirius. Oceannerva ricocheted off as it hit the shard, causing Shakil to stagger, then the shard spun around exactly like the Sandstone Archer’s arrow had done earlier that day and soared towards him. He threw himself backwards, but the shard struck his chest as it whizzed by; dribbles of scarlet streamed into the water.

Milius pelted his own oncoming shards with jets of boiling water, so that they melted instantly. Then he whipped around to face Shakil. Streams of scalding water streaked across the murky expanse, and the shards dissolved around him. Out ahead of them, Phontus was laughing.

Sirius was striking madly at his enormous hand, but though he tried to snatch it away at the very last second, angry red burns still bloomed across his lustrous, sapphire skin. As Sirius raised Vulcatrix to swing again Phontus swung out with his own arm. He caught the blade in his huge fist, and though he grunted with pain and rage, he held on long enough to swing out with his other fist. Sirius went soaring away across the dark water.

“SIRIUS!”

But Phontus was not yet done. He waved his massive arms again and sea foam blossomed out of nowhere, coiling and distorting, apparently taking shape; a moment later, a dozen huge, midnight-black horses were standing there. They darted towards them with neighs of fury, tossing their gargantuan heads, but before Milius could do anything, thick, pearly mist erupted across the dark expanse, obscuring the nightmare horses and the bewildered king, who continued to shout through the gloom.

“WHAT — ? WHAT IS THIS?”

Shakil seized the opportunity to swim over to Milius, his sapphire aglow, the stone tablet clutched in his hand.

“Time to put that crown to the test, I think,” he said with a wink. Milius stowed Palpatunde in its sheath, then pulled out the wreath of braided gold that he had brought with him. He placed it atop his shock of dark hair and looked ahead as Shakil waved Oceannerva; the mist cleared at once.

The dozen midnight-black horses and Phontus came into view; the dark steeds galloped across the water again, their blank red eyes gleaming — but they were suddenly repelled backwards with a sonorous crash, for a dome of red had appeared without warning, encasing Milius and Shakil.

It was Sirius, swimming towards them with his goblin-like figurine aloft, smeared with blood that trickled down its surface, unperturbed by the water around them.

“Knew this would come in handy,” he said brightly. Phontus screamed with rage as the horses hammered against the barrier with their elephantine hooves, and the water around them erupted, pelting against the barrier with gale force. But the barrier held. When the water had settled again, Milius looked out at the horses, concentrating deeply. He forced himself to block out his surroundings, the sight of Phontus’s face twisting in fury, the sound of the dark horses pummeling against the barrier. . . .

And he felt himself settle, felt his own calmness stream from the wreath atop his head, as though it were a plume of gas, diffusing into the water. . . . And miraculously, moments later, the horses settled completely, drifting serenely in the water.

“What's this?” Phontus demanded. “What are you doing? Keep going!”

But the horses did not move. Milius swam forward as the barrier dissolved in front of him, stopping only when he had reached the side of the dark horses, staring placidly out at Phontus. “Seems like they've decided they don't want to fight anymore, don't they?” he said lightly, reaching out and stroking the mane of the horse closest to him, which whinnied gently.

“IMPOSSIBLE!” Phontus screamed. Milius moved as quickly as he could, unsheathing Palpatunde and swiping at the same horse he had just nuzzled, which sank lazily out of sight as the blade absorbed its energy.

“NO!”

The water rippled around them, and enormous balls of what looked like pale green gas suddenly appeared in the water. They exploded, the great blast flooding towards them. With a single thought, Milius encased himself in a ball of ice and thrust himself forward. He felt the force tearing at the ice as he soared through the water, but it held until he stopped directly in front of Phontus himself, who looked taken aback. The energy he had absorbed burst out of the blade as Milius smirked, knocking him off balance.

As he struggled to regain balance, Sirius came hurtling out of where. Vulcatrix blazing, he took a great swipe at the king's knee. A huge, terrible slash appeared across his skin. Phontus shrieked with pain as rich blue blood bloomed out of the gash, which was searing red.

“Pesky Knight!” he spat. “You and your disgusting fire have no place under the sea!”

He lunged, but before he could touch Sirius a loud rumbling sound drew his attention. He looked up to see a huge black rock above him bursting apart, Shakil floating at its side, Oceannerva buried in its surface; Sirius swooped away as, with a colossal crash, the whole mass tumbled down upon Phontus, who, with his incredible size, was unable to evade the falling rocks.

Phontus was buried under the rubble. For a moment it seemed that they had won — then Phontus screamed; a howl of rage accompanied by the force of a typhoon. It blew the rubble away; Milius summoned another wall of ice to defend them, but it shattered under the force of the pelting rocks.

Then a brilliant blue light illuminated the dark water. Phontus was rising upwards out of the gloom, his entire form glowing.

“Enough of this!”

His voice had changed, an ethereal echo, as though two people were speaking at once.

“You cannot beat me — I am a descendant of the god of the sea!”

“But you're not technically a god, are you?” a voice said slyly. One bewildered second later, a shining golden light added to the sapphire flare and Ariana appeared. She had evidently been cloaked by her Invisibility Potion. Her golden, metallic-looking rope lashed out from her arm and swung through the darkness, extending to an impossible length as it coiled around the confused king, binding him entirely. He shrank back to the size of a regular man, his sudden glare fading.

“What is this?” Phontus roared, struggling against the coils, but he could not break free.

“Golden manacles!” Ariana said smugly. “They bind all magic, you're not going anywhere. Milius,” she added, “feel free to do the honours.”

But Milius did not move. He was gazing at Phontus, who was still struggling desperately against the chains, looking suddenly terrified.

“Milius?” Sirius said uncertainly. "What are you waiting for?"

“What do you know about the building?” Milius asked Phontus, ignoring them both. The others looked stunned, as did Phontus.

“Excuse me?”

“The Catacomb. You say you're the king of the sea; I imagine you'd make it your business to know what this place is?”

“Perhaps. And what of it?” Phontus snarled.

“If you tell us what you know,” Milius said, “we may be inclined to let you live.”

Phontus looked both shocked and suspicious. “And why would you do that?”

“Because I'm feeling nice today,” Milius said in a bored voice. “Get on with it; otherwise —” He raised Palpatunde and ran a finger down the blade.

Phontus’s eyes latched onto the sword for a moment, then he turned away, looking even warier. “I have your word?”

“Probably,” Milius said lazily, with a shrug.

Phontus hesitated. “Yes, I know of it. I'm not personally familiar with the place, but I've been informed. All the past kings have. From what I've been told, it was established thousands of years ago, but not in the sea. It was moved here. By whom, we are told, an ancient generation of Dragonknights.”

Milius’s heart began to race again. He exchanged significant looks with the other Knights, who all looked eager as well, then turned back to Phontus. “Why?”

“To conceal something.”

“You mean this?” Shakil said, raising the tablet.

“Perhaps,” Phontus repeated indifferently. “I was not told, nor were my forefathers.”

“Why was it established in the first place? Why was it moved here?”

Phontus hesitated again.

“Answer me!” Milius snarled, and he swam out to Phontus, hitching the sword point beneath his throat.

Phontus swallowed. “The Catacombs, according to what I have heard, are the birthplaces of your lizards. The places where they were created.”

“So there's one for each of us?” Sirius said wonderingly.

“And there’s something hidden inside each of them?” Ariana asked.

“I don't know what is inside any of them, precisely. Nor why it was hidden here. My people, following both the requests of the Dragonknights and the orders of the first sea kings, have never set foot in this place, and have never set eyes on it since it was first dropped into out depths.”

“Do you know where the others are?” Milius asked. Again, Phontus did not respond.

Milius pressed the point against his neck.

“All right, all right!” he said hastily. “Yes, we know the location of one more — but we weren't supposed to.”

“What do you — ?”

“The prince at the time the deal was made between my people and yours stole an audience with the Ruby Knight of that period. Using an ancient ability that has been passed through the generations of my family, he extracted the memory. But it was with very little time and tremendous effort. The most he managed to glean was that the Catacomb resided somewhere near a volcano.”

“That must be mine and Verdona’s!” Sirius said enthusiastically.

“Fine,” Milius said. “You've been of help. We'll keep our agreement — you can go, on the condition that you drop this stupid revenge agenda. All right?”

Phontus gave a grudging nod. Milius retreated, then nodded at Ariana. Though she still looked hesitant, she jerked her arm and the rope uncoiled at once, snaking back around her arm. They stared at each other for a moment, then, when Phontus did not react, they turned and swam away, Phontus staring resentfully after them. They were almost at the gap in the roof of the Catacomb, however, when it transpired that Phontus did not intend to keep his word.

An enormous shadow suddenly engulfed them, plunging them into darkness, and they whipped around, expecting to see Phontus at full size again — they were wrong. An enormous, monstrous squid was floating above them, twice as large as the one Milius had stolen the pearl from the last time he had been under the sea.

“We had a deal!” Milius roared at him.

“What can I say, deals were made to be broken,” Phontus said, and his tentacles swooped through the water. Milius raised the pearl, ready to retaliate, but Sirius suddenly seized him around the shoulders and pushed him roughly aside, then thrust his fist outwards in Phontus’s direction.

The skull ring on his finger flared with green light and the skull jaws clacked open. A great vacuum seemed to open up in the ring, sucking the squid’s descending tentacles into its mouth. The squid screeched and thrashed, but it could not escape. And moments later, the squid had disappeared into the ring’s mouth, though it was patently too large to fit. The light died down and the jaws clacked shut. Milius, Shakil, and Ariana gaped at him.

"What?" he said defensively. "We kept our word — we didn't kill him."

They fell through the gap and into the Catacomb, where they found all four dragons huddled around Frederick, who was looking positively awestruck.

"You all okay?" Sirius said, speaking to the dragons. All four nodded in unison.

"I've been keeping them entertained until you got back," grinned Frederick, but the dragons did not look entertained at all. On the contrary, they all looked rather annoyed. Sparks were dancing along Lumeus's plates again.

The Knights trooped forward as one, veering towards their dragon.

"Aw, you poor thing," Ariana cooed, snuggling against Vrydius. Aleia and Verdona began to nuzzle Sirius and Shakil.

"You okay, boy?" Milius asked Lumeus. He turned his white marble eyes upon him and nodded. Milius smiled — but quite abruptly, he frowned. He wanted nothing more than to leave this place, for he was unsure whether Phontus's people weren't on their way towards them at that very moment, no doubt having seen them battling their king via Phontus's enchanted castle ceiling —

He gasped, very suddenly and very loudly.

"What?" the others chorused looking rather alarmed.

"The volcano, the one that he was talking about just now — I know where it is! I saw it in Phontus's ceiling!"

"Are you sure?" Ariana said, looking startled.

"Positive. Come on, we need to get back to the Elders!"