He heard it first along the waves, and he thought the heat of the sun might be getting to him. Thomas knew the song: had sung it this voyage, just yesterday, in fact--and now it was reflected back to him in an echo. The birds it was, perhaps, seagulls crying in a way his mind had misinterpreted. Or the wind, or the waves, or simple lightheadedness. As his skipper skimmed slow along the sea he dipped his head in the cool water, felt it drag, opened his eyes to see the sun glimmering off fish scales, to see a not-so-distant face--
Thomas jerked upright, hair bedraggled, wide-eyed and disbelieving. He pulled the sail and slowly, cautiously, dipped his head beneath the waves. With all the care of a man putting his head in a lion's maw. Again, the fish, again the deep blue sea, but this time no slender face. And though he remained at that spot for a time before furling his sails and turning back, he didn't hear the song again that day.

He didn't hear it the next day, for he remained silent. It had been an echo, then, or something like it: he felt certain the truth had outed. The next day he would sing.

He heard it second on the placid sea, perhaps a half hour closer to his home. This time he took in the sails and listened more closely, only to find there had been an error in translation. He let the melody go until he couldn't stand it any longer, opening his mouth and underlining the correct notes in his baritone boom. Out across the waves his correction flew, and for a long moment wasn't returned. Thomas began to think he had imagined the whole thing after all, but then--
~♪♫
Thomas nodded to himself, satisfied. And when other small imperfections appeared he corrected them as well, overwriting the melody that was then echoed, correctly.

He heard it third in a great storm, in a maelstrom sprung up without warning or sense. It cut through the blue-green frothing waves as he thrashed within them, and most unlike an echo it grew in volume. He had a gallon of seawater in him by the time what felt like soft hands buoyed him, bore him to his boat, and his sense was too far gone to recognize the speed of his craft on the return.

He heard it fourth days later, recovered from the storm. The sound the echo made seemed joyous, or perhaps nervous. He sang at the same time, the same pitch, no longer believing it was a mere seabird or reverberation from the glassy sea. He sang the final verse and immersed his head in the deep blue.
He heard it fifth under the water, trilling and sweet, and he watched as the singer approached. Slender, ethereal, snakelike. Glittering scales like a gorgeous, rainbow fish. Warmed, suntanned skin.

He heard it sixth by the sand's edge, and seventh on the rocks. Then he didn't hear it for some time--for after all, they had learned new songs to sing. But he would hear it again on warm days over the glassy sea, and on nights, hummed softly, under the covers of his bed.