The Merman's Children by Poul Anderson

obey. “He does not lack courage,” Eyjan said in the mer-tongue.
    â€œNor does he lack treachery,” Tauno warned. “Turn never your back on any of that scurvy lot.”
    â€œSave Niels and Ingeborg,” she said.
    â€œOh, you’d not want to turn your back on him, nor I mine on her,” Kennin laughed. He likewise felt no fear, he was wild to be off.
    Using a crane they had fitted together and braced against the mast, the sailors raised that which had been readied while under way. A large piece of iron had been hammered into the boulder till it stood fast; thereafter the outthrusting half was ground and whetted to a barbed spearhead. Elsewhere in the rock were rings, and the huge net was secured to these at its middle. Along the outer edges of the net were bent the twelve ship-anchors. All this made a sort of bundle lashed below a raft whose right size had been learned by trial and error. The crane arm dangled it over the starboard bulwark, tilting the cog.
    â€œLet’s go,” said Tauno. He himself was unafraid, though at the back of his head he did think on the fact that this world—that entered him and that he entered through senses triply heightened by danger—might soon crack to an end, not only in its present and future but in its very past.
    The siblings took off their clothes, save for the headbands and dagger belts. Each slung a pair of harpoons across the shoulders. They stood for a moment at the rail, their sea ablaze behind them, tall Tauno, lithe Kennin, Eyjan of the white skin and the comely breasts.
    To them came Niels. He wrung their hands, he kissed the girl, he wept because he could not go with them. Meanwhile Ingeborg held hands and eyes with Tauno. She had braided her hair, but a stray brown lock fluttered across her brow. Upon her snub-nosed, full-mouthed, freckled face had come a grave loneliness he had never known before, not ever among the merfolk.
    â€œIt may be I will not see you again, Tauno,” she said, too low for others to listen, “and sure it is that I cannot and must not speak what is in my heart. Yet I’ll pray for this, that if you go to your death, on your errand for a sister’s sake, God give you in your last moment the pure soul you have earned.”
    â€œOh…you are kind, but—well, I fully mean to come back.”
    â€œI drew a bucket of sea water ere dawn,” she whispered, “and washed myself clean. Will you kiss me farewell?”
    He did. Her pretense of dislike was no longer needful, he supposed; his alliance could guard her, as well as each other, on the homeward voyage. “Overboard!” he shouted, and plunged.
    Six feet beneath, the sea took him with a joyful splash. It sheathed him in aliveness. He savored the taste and coolness for a whole minute before he called, “Lower away.”
    The sailors cranked down the laden raft. It floated awash, weight exactly upheld. Tauno cast it loose. The humans crowded to the rail. The halflings waved—not to them but to wind and sun—and went under.
    The first breath of sea was always easier than the first of air. One simply blew out, then stretched wide the lips and chest. Water came in, tingling through mouth, nostrils, throat, lungs, stomach, guts, blood, to the last nail and hair. That dear shock threw the body over to merfolk way; subtle humors decomposed the fluid element itself to get the stuff which sustains fish, fowl, flesh, and fire alike; salt was sieved from the tissues; interior furnaces stoked themselves high against the lamprey chill.
    That was a reason why merfolk were scarce. They required more food afloat than men do ashore. A bad catch or a murrain among the shellfish might make an entire tribe starve to death. The sea gives; the sea takes.
    Vanimen’s children placed themselves to manhandle their clumsy load and swam downward.
    As first the light was like new leaves and old amber. Soon it grew murky, soon afterward