The Syrena commissioned for the task of re-creating the roads proved meticulous in placing each recovered cobblestone paver into a perfect sphere of winding paths leading to the palace in the middle. Though gliding through the water above it, Galen and Romul follow the fragmented road as they pass buildings and fountains and public baths. Galen can easily imagine an ancient population bringing life to this desolate, inanimate place, exchanging their abundance of gold, silver, and copper for food, clothing, and services. But what about people who look like Emma?

Galen gets his answer as they round the last bend to the palace. His breath catches as they approach a wall he’s seen a thousand times before but never really looked at. Images of humans sacrificing large bulls in honor of Poseidon. Most of them have black hair, olive skin, violet eyes. Rigid lines are drawn on their torsos, probably to emphasize their physiques. But in the corner of the panorama, there are other humans. Humans he’s never noticed before because their outlines almost blend in with the wall. White skin. White hair. Violet eyes. Humans who look like Emma.

Galen clears his throat. “These humans here,” he says, running his finger over one whose soft curves remind him of her. “Who are they?”

“My prince, none of the images on this wall are of humans. These are our Syrena brethren in their human forms. And these,” he says, his voice filled with disdain, “are the half-breeds. These in particular, sired of Poseidon himself.”

Galen stiffens against the bitterness in Romul’s tone. “Right. I think you mentioned them before. Something about abominations … I can’t remember exactly. Why were they hated?”

Romul shakes his head. “They themselves were not hated. No, my young friend. In fact, Poseidon loved his half-human offspring very much. That was part of the problem. Many of our brethren sacrificed themselves for their human mates.”

“Sacrificed themselves? What do you mean?”

“It is in our collective memory that many of our ancestors chose to spend most of their time on land,” another voice calls from behind them. Galen and Romul turn to see Atta, an Archive of the house of Poseidon.

Romul smiles warmly at her. In the Cave of Memories, there is no division of houses. “Atta, welcome.” He turns back to Galen. “Yes, she is correct, young friend.”

“But what’s wrong with that? Spending time on land?” Galen wishes he would have phrased the question better; it sounds a little like questioning the law. Like treason.

“Our bodies are not suited for land, my prince,” Atta says, skimming her small hand along the wall in a sort of reverential way. “The … heaviness … on land makes our bodies work harder than they do in the water. It makes us age faster.”

“Heaviness?” Galen says, mulling over what she could mean. He turns to Romul. “Is she talking about gravity?” Of course. That’s why he’s so tired at the end of a school day. It takes more energy to move his body around on land than floating, almost weightless, in the water. Much more energy. A small flick of his fin gets him triple the distance than using the same effort to move his human legs.

Romul nods. “Yes, gravity, very good, Galen. The Syrena population began to decrease very rapidly, because many of our brethren chose to stay on land with their human mates and die a human death. Triton knew if that continued, our kind would eventually disappear.”

It makes us age faster. Galen remembers what Dr. Milligan said about heart rates. The faster the heart rate, the shorter the life. During this last visit, Dr. Milligan had said Galen’s heart rate was faster than when he’d checked it just months before. Because I’ve been spending so much time on land.

His throat constricts. “These half-breeds. What were they like?”

Atta and Romul exchange a look. Romul says, “I’m afraid we don’t understand the question, my prince.”

“What I mean is, were they able to change into Syrena form? Did any of Poseidon’s half-human offspring inherit his gift?”

Romul knits his brows. Atta folds her hands in front of her. She says, “Not that we recall, Highness. It is our shared understanding that the half-breeds were never able to change into form. It is thought that none inherited Poseidon’s Gift.”

“It’s thought? You’re not sure?” Galen says, his frustration growing.

“My prince,” Romul says, “it is possible that they inherited his Gift. The Law of the Generals requiring the two houses to mate was not put in place until after Tartessos was besieged by humans. We cannot confirm if any of Poseidon’s half-human offspring inherited the Gift, as they were all destroyed in the great waves of Triton.”

Emma can hold her breath for a long time but not indefinitely. Depending on how long Triton pounded the shore, the Half-Breeds very well could have been wiped out. Still, some could have lived, couldn’t they? He stares at the Half-Breed on the wall, the one who reminds him of Emma. It turns his stomach to think she drowned.

Lost in his self-torment, he stares at the image long enough to bore his archive companions. “Highness, may we be of further use to you at this time?” Atta gently coaxes him from his trance.

Galen nods. “I have one more question, Atta, if you don’t mind.”

“Of course not, Highness,” she says graciously.

“The Half-Breeds. Were they very bad? Did they turn against us? Is that why Triton destroyed them with the humans?”

“No,” she says. “Triton felt they should be destroyed because of what they stood for. He did not want Poseidon to be reminded of his human mate or his half-human offspring. He did not want any more of our kind to be tempted to live—to die—on land. He believed our survival depended on our staying below the surface, away from humans.”