If you asked Pai why it was he had decided to go into marine biology, he would have had plenty of answers: the oceans are the greatest scientific mysteries on earth today, they contain a level of biodiversity that is, frankly, breathtaking, careful study of vulnerable ecosystems is vital if we wish to preserve them. Et cetera.
The real reason was that the bottom of the ocean was about as far away from people as it was possible to be. When he dived, as he sometimes did, to collect samples of coral or sediment, no-one tapped him on the shoulder to see how his work was getting on. Jellyfish didn't ask stupid questions. Cetacea, the field he found himself drifting towards, had the companionably warm eyes of mammals but did not talk back.
(Or so he had hoped.)
"Pai!" He jumps, swiping his pencil across the notes he had been carefully making while studying readings from the monitor in front of him.
"Is it impossible for you to enter a room like a normal person?"
"And you're the authority on normal people, are you?" Kish settles himself comfortably, arms draped over the back of a chair. There are quite a few empty chairs - the little office was usually empty, except for Pai.
Pai growls and keeps his eyes fixed firmly on the screen. Just as trying to swat a fly would only cause more frustration, he had learnt that the easiest way to deal with Kish was to ignore him. The younger man leans over his shoulder, pretending to be absorbed in Pai's work. His lip twitches with irritation.
"What's that?" Kish is pointing at a small spike in the readings, highlighted in red.
Automatically, Pai knocks his hand away. "Don't touch that," he snaps. A look of triumph flashes across Kish's face. Pai heaves a sigh. "How did you get in here, anyway? I asked not to be disturbed. I think I might have mentioned you specifically, actually."
"Oh, I have my ways."
Pai doesn't doubt it. Kish can be charming when he wants to be, all long eyelashes and devilish smiles. They looked alike - everyone said so - but he had never been able to emulate him; he was too tall, too gangly, too awkward, too prone to blushes that clashed embarrassingly with his pale skin.
It was a wonder Kish kept him around, as image-conscious as he was. But he had. As he had grown up and tried to move away from his adolescence, first to university, then to this tiny research facility tucked against the coast, he had managed to shed most of the people around him, but Kish had stuck. He had made endless excuses to visit, eventually moving close by for school himself - science, as well, Earth Sciences, although Pai was fairly certain he hadn't attended classes for about a year.
"Why are you here, then?"
"I need an excuse to visit my dear, solitary brother? Cold-hearted, aren't you?" Pai gives him a look, and Kish continues hurriedly. "And I wanted to check up on you. Taruto's getting worried, you know. You haven't called home in months."
He reaches into his satchel and pulls out a wrapped box that Pai could see contained a sizeable quantity of leftovers. "And, according to the person at the front desk, you haven't been seen in the cafeteria for days."
"I've been busy."
"So I see." He peers over at the screen again, and Pai, though he frowns, doesn't try to stop him. "What's that?" He repeats doggedly.
Too late. The fly obviously wasn't going to leave him alone. "I don't know. We've got systems in place to pick up sound waves, you know, the calls of whales and dolphins, and porpoises. To track their populations, and to see if their mating calls are personalised; you get the idea."
"Yeah, so?"
"Well, this part here, that's unusual." Despite how irritated he is at his brother, Pai finds himself warming to his subject. "The frequencies are nothing like what we've seen before. A completely different pitch… it's definitely not a whale or a dolphin. Or a porpoise, for that matter." He pauses, a little embarrassed. "Actually, I have no idea what it is."
Kish gives him a knowing look and a small, mischievous grin. "But you're going to find out, aren't you?"
He shrugs. "I suppose I might. Not that it's any of your concern." A dismissive wave of the hand. "Thanks for the food. Say hi to Taruto for me."
"Aw, Pai…"
Pai considers, groans inwardly, makes a sacrifice. "If he wants to stay over the summer for a while, he can. All right?"
Kish's grin gets alarmingly wider and he looks like he's about to say something, so Pai quickly adds, "For a few days. Maximum."
Kish was right, of course. Pai likes to give off an aura of cool detachment towards everything, even his work - it makes it easier to deal with people, if you make it clear you don't want to - but underneath there is a powerful spark of real curiosity. It fills him with a childish excitement, knowing that there is a solution (and there is, there always is) and he can find it. So he barely waits an hour after Kish finally leaves him in peace to gather his diving equipment and head for the water.
He doesn't need to go himself, he thinks as he pulls on his wetsuit. He could have asked someone else to go, someone more experienced, and in fact a few days ago he had been close to dismissing the sounds altogether as a technological glitch - until they had appeared again, at almost the exact same time.
But those methods, Pai allows himself to admit now that he is alone, would not be nearly as fun. Some days he felt he was made for the water, his long limbs seeming almost elegant as he swam, the ripples above hiding him from prying eyes, his breath -
He stops himself. With scientific care he checks his oxygen and breathing apparatus, and dives.
He takes his time swimming to the rocking outcropping where they've placed the recording equipment; whatever is making the noises seems to come in the evenings, just as the sun is beginning to dip into the sea, and it's pleasant to watch gold spill silently around and above him as daylight fades. At one point he hears telltale chitters echoing through the water, and looks out to see a pod of dolphins; the usual pattern of whale-watching is reversed, and they are out of sight as their bodies crest the water, before dipping back into view.
After reaching the little machine he allows himself to rest against the rocky wall. No obvious damage, he thinks, but fussily checks and re-checks - it could have been knocked by an animal (they've lost three cameras to overly-curious seals in the past year) or by debris thrown by the the tide, or perhaps it was not as waterproof as they thought. Maybe he should take it back to the lab, just in case -
A sudden noise makes him tense, letting go of the equipment. But 'sudden' is the wrong word; the sound came floating, near-literally, over the water to him, quiet at first, and carrying that haunted quality that all sounds underwater seem to have.
'Noise' was not the right word, either.
It's a song.
Pai has heard whale-song before. There's a library of past recordings back at the centre, and Pai's listened to them many times - sometimes for work, sometimes just because he wants to. He has even, a few times, been lucky enough to hear them in the wild. So he thinks at first that that's what he's hearing now, these long, wavering notes that seem to flow straight through his body, and he closes his eyes - but something about the song seems to tease at the edges of his mind, unsettling him.
Then he realises - but no. It has to be a trick of the mind, he thinks, a side-effect of being underwater, of being, if he tells the truth, utterly exhausted, of the long-suppressed worries Kish's visit had brought to the surface.
It's impossible. The sound - the song - can't be a human voice.
Even the thought, the sheer impossibility and wrongness of it, stands his hair on end under the wetsuit. No human voice could be that melodic, could carry so far, could have that warbling quality to it that sends a reverberation through Pai's heart. Stupid. You are being stupid, he tells himself, even as, through instinct, he shrinks against the stone. A crust of shellfish (idly, he wonders what species) digs into his back. Scared? Really? You swim all the way out here, Pai, you idiot, and now you're going to miss -
The figure comes out of the blue shadows cloaked in its song, although it moves through the water silently. At first, Pai is relieved; the shape suggests a porpoise, or perhaps a small dolphin. But something still keeps Pai from moving into the open water, out of his hiding-place.
The last of the the day's light falls into the water, glittering on its surface. It also falls onto the back of the swimming body. Pai stares.
Smooth, shining tail, a grey pale as moonlight. And then - skin. Skin that's not grey, but looks warmed with the sunlit sea. Arms, with hands slightly outstretched.
Sure, Pai's not been in the field that long, but he's fairly certain cetaceans don't have arms.
Or hair that streams out behind them as they swim. Green hair, so he thinks it must look, from above, as if seaweed's being carried by the waves.
Pai's not stupid, despite what Kish might say. Of course he's heard of - he won't say it, not even to himself.
Because it's ridiculous. Because it's impossible.
Mermaids don't exist.
As he's telling himself this - repeatedly - she passes by. He flattens himself even further against the rock, but, perhaps because she's so absorbed in that beautiful song, she does not seem to notice him at all.
He catches a glimpse of wide, green eyes. And a dappling of freckles. As that tail slides past him, he notes its shortness, its slight chubbiness compared to the dolphins he had seen earlier. A porpoise, thinks the last part of Pai's mind able to form coherent thoughts. Definitely a porpoise.