She finds the paper she’s looking for and skims over it.

“It’s worth noting,” she says, “that beach erosion and potential oil and gas drilling operations are the primary threats to the Trigonum ecosystem.”

“Beach erosion,” I repeat, “and drilling operations.”

“Human tourism is also a major concern in this kingdom,” she continues. “As are commercial fishing and water pollution.”

I try to keep a mental tally, but it seems like the list of problems is very long. And this is just one of ten kingdoms. I have a feeling my surveys are going to be quite full.

“But maybe the most important, though tragic, fact,” she says, looking up from her notes, “is the death of the king’s son last fall.”

“Oh no,” I cry. “What happened?”

“Prince Cirren was a scientist,” she explains. “He was leading a research expedition to the Trigonum Vortex when a flash whirlpool appeared and wiped out the entire expedition.”

“That’s terrible.” I can’t imagine the impact of such a tragedy on the king. He must have been devastated. “Are those kinds of incidents common in Trigonum?”

“They aren’t unheard of,” Peri answers. “That’s how the Trigonum Vortex got its reputation. But supposedly they are happening more frequently. And with greater intensity.”

The waters of Thalassinia are relatively calm. Other than the occasional hurricane that churns the surface but leaves the depths undisturbed, we don’t have many natural disasters. It must be stressful to live somewhere where they happen all the time.

“That information helps a lot, Peri,” I say as we continue our northerly swim. “I’m sure it will help to go in knowing some of what’s going on.”

She swims close to my side. “I thought so.” She tucks the folder of kelpaper notes into the messenger bag slung across her body. “I’m glad I could help.”

I take her hand.

“It definitely helps to have my best friend at my side.”

We swim along in silence, and I let my attention drift to the world around me. Everything is quite still. There are few fish in the stream of the faster-than-usual current. I glance up. I can see far above, just beneath the surface, the hulls of several boats. From this distance I can’t tell if they are pleasure boats or commercial fishing boats or even scientific expeditions.

As I watch, something splashes into the water next to one of the boats ahead of us. A trail of bubbles spirals down, falling just in front of the lead guard as we pass. I crane my head down to see where the object lands, and when it does, I’m appalled to see that it’s a glass bottle.

“Gross,” Peri says, seeing the same thing.

I shake my head. “Why would anyone think they can use the ocean as a trash can?”

“Some people just don’t think about it all,” she says.

Sad but true.

Even sadder, as we swim by, I see the seaweed forest along the ocean floor littered with all kinds of human trash. Shopping bags, tangled-up fishing line, even a big, bright-blue plastic barrel. It’s awful.

“This is where we change course, Princess,” Captain Frater says. He makes a quick hand gesture, and the school of guards turns as one and sets a course to the east.

We’ve kept pretty near the shore until now, for more than two hours. With the magical boost to the Gulf Stream from Daddy’s trident—just one of the royal powers that comes with being king—the complete journey only takes us a little over three hours. We’re swimming to a stop in front of the palace before I know it.

Peri takes her position as emissary very seriously and insists on being the one to officially announce our presence. She swims up to the front, which looks to the human eye like an abandoned shipwreck, and clangs the bell on the stern of the ship. Within moments, a pair of uniformed guards, wearing the dark teal and gray colors of Trigonum, slide open a hidden steel door.

“Who calls?” one of them asks.

“Crown Princess Waterlily of Thalassinia,” Peri replies. “She seeks an audience with the king.”

The two guards, twins, look at me and nod.

“Please come in, Princess,” one says. “Prince Tellin is waiting for you.”

The other adds, “We will notify King Bostrych immediately.”

“Thank you,” I say, trying to sound regal. “Please tell his highness it is a matter of some urgency.”

“Yes, Princess.”

With that, they leave us in the entry hall as they go to inform the king. Tellin and a single pair of Acroporan guards are waiting there, too.

“Are you ready?” Tellin asks with a nervous smile.

The message I sent him, asking him to meet me here today, outlined the basics of my plan. He knows what we’re asking for and what the next steps are.

“Absolutely,” I say, more confidently than I feel.

“His Highness King Bostrych of Trigonum,” one of the twin guards announces as they both swim back into the hall, “invites you and your contingent to dine with him in the formal dining chamber.”

My contingent and I follow them into the palace. I’m in the lead, with a guard on either side. Then Peri between another pair, and Tellin between his. Finally, my last two guards bring up the rear. We’re quite a parade.

We pass through the halls of the shipwreck, narrow passageways lined with saltwater-preserved wood and rusted hardware. Eventually we pass through a large opening—like a giant hole in the side of the ship—and into a more merlike structure. Carved from rock and reef, the heart of the Trigonum palace is not so different from my home in Thalassinia. Rounded halls and spiraling ramps. Pearl-crusted frames around mosaic portraits. But where everything in Thalassinia sparkles with gold and gems, the details here are more modest. It is apparent that Trigonum does not possess the wealth my kingdom does.