Yundah = seal-woman
Selkies = seal-folk with the ability to shed their skins and become human
Girvan = young, rough boy
Muriel (Muireall) = sea-maiden
I'm playing a bit with the actual lore to suit my purposes, but it's basically the same. This is set in the same country as "Maid on the Shore," but further down the coast.
"And don't come back until you've done something useful, boy!" Girvan ran out of the kitchen with his arms raised over his head, and paused only to grab his flute before trotting down the path to the shore. As he passed the forge, flute in hand, his father glanced up and shook his head.
"How any boy of mine would be satisfied with games and nonsense, I don't know," the man rumbled over the noise of the bellows. "Your name means Rough, boy, live up to it!" Girvan grinned at his father and didn't respond. The constant gripes made no mark on his tough hide, and he went his own way.
His own way led always to the ocean, and a lonely stretch of land bound by cliffs. Here Girvan played his flute and taught himself new songs, composing words in his head that never touched the air, since he hadn't figured out how to play and sing at the same time. Today he was working on a song he felt had been written by the sea itself, and perforce was moving slowly. He lost track of time in the flow of the music, and when he came back to himself the sun was setting. In the sea in front of him sat a seal, staring at him with huge, fearless brown eyes.
He stopped playing mid-note. A seal at the shore! What was it doing here? Those were creatures fearful of humans, normally. In the back of his mind Girvan knew that this particular bit of land was never visited by other people, because there were no fish and it was hard to get to. But still! The seal might be a Selkie, and if that was the case… what a song that would be!
The seal moved as if startled when the music stopped, and fled back into the water. Girvan half rose from his seat in an aborted attempt to stop the animal. "No, wait-"
Muriel floated in the deep water, watching the men hauling fish on their boats. How incredible was it, the dexterity of human hands! Tying knots on the fly, grasping nets in flexible fingers and prying open jars with fingernails no larger than an eye. And the people didn't recognize these gifts the gods had given them. Muriel herself could hardly wait for the nights when she could break free of her skin and assume the form of a human – most nights she simply sat on a rock near a lonely shore and admired her fingers. Sometimes she would dare the beach and draw in the sand, creating fanciful patterns with one, two, or all five fingers, lines and swirls denied her in seal-shape. Her mother and father scorned her yearnings, and told her to give up her childishness. She was seal-woman, a Yundah, and could have so much more than merely fingers and ephemeral drawings in the sand!
One night several months ago she had headed eagerly for her beach, arrowing through the water until the ground began to rise. Then she broke the surface and froze. There was a human boy on her beach, sitting cross-legged with his eyes closed. His long-fingered hands were wrapped around a strange item held to his mouth, and it was producing the most captivating sounds Muriel had ever heard.
It sounded almost like a voice, like a long drawn out note flying over the scales and down into sharp discordances that resolved a few moments later. It put her in mind of the ocean itself, and sent her swooping across the ocean floor in her mind's eye. Abruptly, the music had stopped, and Muriel came back to herself to see the human boy staring at her. Suddenly frightened, Muriel turned and sped back into the water, away from the boy who was unlike any she'd seen before.
Over the next few days Girvan seemed to be hearing about seals and Selkies everywhere. In the forge, his father's apprentices swapped ever-expanding stories about the beautiful seal-maidens they'd seen on the shores near the harbor and how they'd steal one to wife. In the market, housewives gossiped about the men who'd left town, probably in the clutches of scheming seal-maidens who lured them beneath the waves. Fishermen spoke of seals stealing their catches before they could get to them, trappers of the impossibility of catching one.
Girvan's curiosity grew hotter and hotter as the weeks passed, making him nearly jitter out of his skin whenever he was away from the seashore. Which was the truth? Was there a truth? Girvan became very good friends with the elder folks in town. No one in living memory had seen a Selkie shift shape, but his neighbor's grandfather remembered hearing about how his father's uncle had disappeared under mysterious circumstances while night fishing one evening. The seals were known to be Selkies, but that might be local legend as much as truth. The most striking individuals in town were called Selkies, but it might just be compliments.
Girvan went back to the beach every clear night, trying to see if that seal was more than just an unexpected audience to his playing. If he could meet a Selkie, that would be the best moment in his life! Just imagine, ill-named Girvan would be the first to talk to a Selkie! One who wouldn't laugh at him. And perhaps he'd have a friend as outcast as him.
Muriel avoided the beach for weeks. The gulf between wishing to meet a human and actually doing so was vast indeed, and not one she was prepared to cross right then. After a while her fear decreased and her curiosity increased. What exactly had the boy been doing? They had music in the Sea Hold, of course, but it was all vocal. This reminded her of voices, but it had elements a real voice couldn't attain. The purity of tone ached, and it resonated in her bones all through the winter. On clear days she would return to the beach and lurk behind a submerged rock, listening to the boy play his sea song and feeling the notes huddle in her throat. In the sea she was safe, but on land she could sing…
As spring came again, Muriel ventured close to the shore once more, half hoping to catch the boy at his mysterious music without the interference of water, and half hoping he'd have given up and given her back her beach. That evening the beach was empty and Muriel swam up the sand until she was only half covered, then wriggled out of her skin and stood up. Stretching, she got her land legs under her and walked out of the sea. No matter how alone she might be, caution while on land had been drummed into her from a young age. One side of the strand consisted of a pile of boulders, and here she lurked with her sealskin wrapped around her, digging her toes into the sand and humming the tune the boy had played. As the sky darkened she expectantly watched the far end of the beach. There! Slipping around behind a boulder, Muriel watched the boy settle himself in the sand and take out his hollow stick. She held her breath as he began to blow, carrying her away on his song of the sea.
Girvan never set down notes to this song, it was only an expression of his feelings for the ocean. And recently, it had become an expression of his wish to meet the Selkie. Sometimes he thought he heard a splash in the dark water, or a shadow in the moonlight, but nothing certain. He began to dream about the Selkie, that it would be a girl with long hair and pale eyes, dressed in a seal skin and standing in the waves. She would laugh with him, not at him. These thoughts communicated themselves through his flute, and it was almost as if he could hear his seal-maiden singing with him. Slowly he became aware that he wasn't just imagining it – he could hear a voice following his tune!
The woman singing was anticipating his next note and harmonizing in a way he'd never heard before. He faltered in the sudden realization, and stopped playing. The voice continued until it too realized the silence then abruptly cut off. Girvan jumped to his feet and ran across the sand. "Wait! Let me talk to you!" But he heard a splash in the water and all he saw was a lithe shape collapse into the waves.
Girvan fell back onto the sand, eyes wide. A Selkie! A Yundah! He sat there for a long time, unable to think, until his legs grew numb. Then he got to his feet. "I don't know whether you're still there. But… please don't run away from me. I just want to play music with you. Spend time with you. Just… be friends?" He waited a long time, but got no response, and eventually turned for home.
Muriel's eyes were equally wide in her seal-shape beneath the waves. She had heard the boy's words, but thought she heard more in them that he realized. If she gave him a bit of her company, eventually she would spend more and more of her time out of her skin, and that was vulnerable. Perhaps right now he was innocent, but it could all too easily turn sour. She stopped and looked back again, to see the boy kneeling on the sand a staring at the water with longing in his eyes. She wavered. It was safe in the ocean, but – the music! The music she had only found on land. And the chance to see what the hands of his could do… At night, when her eyes were better than his, perhaps they could create music together, and she could watch his fingers play along his hollow stick. But… no longer than that.
Muriel climbed up to a standing boulder and began to sing again, arresting the boy's walk toward the cliffs. He turned and ran to the water's edge, and Muriel stopped singing, holding her breath. He could see her, she knew, but he couldn't get to her, or her sealskin. The boy hesitated, then smiled, backed up to sand, and began to play.
Over the waves, you call to me
Shadow of dream, ancient mystery
Oh how I long for your sweet caress
Oh how I long for your gentleness
Torn between sea mists and solid land
Nights when I've ached for a human hand
I'll come to you while the moon shines bright
But I must go free with the first streak of light