Yu Narukami had spent most of his life trying to unlearn fear, but it was difficult when fear had been taught to him like scripture. The town he grew up in clung to the ocean, something to be respected not just for its power, but for what it supposedly held. Old sermons warned of things that lived there, creatures that looked human enough to fool you, that sang or spoke or smiled just right, and lured the “tainted” down where they belonged. As a child, Yu had listened, stiff-backed in a wooden pew, hands clasped too tightly together, convinced that one wrong thought could mark him.

Back then, everything about him had felt like it could be wrong. Especially Yosuke.

Yosuke Hanamura completed him. Yu remembered the way his chest would tighten around him, something warm and terrifying all at once, something he didn’t have words for except the ones he’d been given—sinful, unnatural, wrong. He hadn’t known what it meant to like another boy. He had only known it felt dangerous, like if anyone noticed, the sea itself might rise up and take him for it.

Then, one day, Yosuke was just… gone.

There had been nothing anyone could point to and reason with. He was last seen near the water, and that was enough. The explanation settled quickly, neatly: he must have drowned. It was tragic, people said, but not unthinkable. After a while, people stopped mentioning it at all. Ten years passed, and the absence he left behind became just another quiet part of the town.

Yu tried to let it become that for him too.

By the time he left for college, he had shed most of what the town tried to press into him. He didn’t know what he believed, if anything, beyond what he could see and study and prove. Marine biology made sense in a way those stories never had. As for himself—he had figured that out, slowly, carefully. He knew now that what he’d felt back then had a name, and that it wasn’t something that made him broken. Even so, it hadn’t been replaced. He didn’t fall in love, or want easily. It took closeness, trust—something that hadn’t come again since.

Yosuke had been the only one. And Yosuke was gone.

The morning he returned to the shoreline for fieldwork, the air felt heavier than he remembered. The tide had pulled back farther than expected, exposing slick rock and shallow pools that reflected the pale sky. Yu moved carefully across them, attention split between his footing and the notes he planned to take. It was quiet in a way that wasn’t entirely comfortable, the usual crash of waves muted, like the ocean was holding its breath.

He noticed the movement because it didn’t fit.

At first, he thought it was just light—sun catching the water at the wrong angle, bending something ordinary into something strange. But it shifted too deliberately, just beneath the surface of a deeper inlet. A pale shape, half-hidden, moving with a kind of cautious awareness that made something in his chest tighten. Yu found himself leaning closer before he could stop himself, brows drawing together as he tried to make sense of it. It wasn’t any fish he recognized, nor a seal, nor anything that matched the catalog in his head.

Then the water broke.

Yu recoiled so abruptly his heel slipped against the rock, a jolt of panic shooting up his leg as he caught himself. His breath hitched, sharp and uneven, as his mind tried to reject what he was seeing even as his eyes refused to look away.

...Yosuke. The name surfaced before Yu could stop it, heavy and disbelieving, dragging ten years of buried memory up with it. It didn’t make any sense.

The thing in the water tilted its head, watching him. The movement was achingly familiar. So was the smile that followed. But Yu knew, with a certainty that made his stomach drop, that it wasn’t the same.

“…You’re not—” he started, and his voice faltered, the words catching somewhere between denial and fear. He swallowed hard, forcing himself to keep looking even as every instinct screamed at him to back away. “You’re not him.”