Early one morning, a seal swam to shore on a beach that seals did not normally frequent, for it was too heavily populated by humans.  Not at this hour of the morning, however; no one was on the beach to see her.  She waddled up the beach a ways, to high tide line and a little beyond, and then contorted herself in a way that seals rarely do, shucking off her skin and revealing herself as a tall woman with tan skin and black hair.  She picked up the sealskin, folded it, and tucked it under her arm, then with a cautious glance around, walked up the wooden steps that crossed the dunes and connected the beach to one of the beach houses.  Here, on the back porch, there were several towels and swimsuits hung out to dry.  The woman stole, or perhaps borrowed, a one-piece woman's swimsuit, teal with yellow trim, and covered her nakedness.  Then, with another glance around, she returned the way she had come, and, looking around again, hid her sealskin under the wooden stairs.

In human form and dressed decently enough for the casual atmosphere of various seaside establishments, she walked further along the beach to a set of public access stairs and set out to explore the island for the day.

-----

Seventeen hours later, well after sunset, the woman returned to the house she'd borrowed her swimsuit from, walking down the beach from the pier.  She had enjoyed her day, but she was looking forward to returning to the sea, and to her sisters.  She'd be repaying the borrowed swimsuit with interest, since she couldn't take her shorts or sandals into the sea with her.  Of course, she might have to hang around the beach for hours until everyone staying in the houses along this stretch of beach went to bed, but she might as well scout the area now, in case it was already possible to go.

Oh, no.

There was a teen boy sitting on the wooden steps where she'd hidden her sealskin.  And it was lying across his lap.  The fate her sisters had warned her against, which she had avoided by good luck and cleverness so far, had come upon her; she would have to do whatever he wanted to get her skin back, and she might not get it back for years.  The good news was that a boy that age wasn't likely to force her into a thirty-year marriage, like too many men had done to her sisters.  He'd probably just ask her to let him see her breasts, maybe to fondle them... or at worst, one sex act and she'd be free to go.  And who knows, maybe he'd be fool enough to acccept fairy gold for it, such as had paid for her sandals and shorts and her meals.  Or... she could try to just bluff her way through.

"That doesn't belong to you, young man."

He looked at her appraisingly.  "Yeah, and that swimsuit you're wearing doesn't belong to you, either.  My sister's been mad at me all day, she thinks I stole and hid it for a prank.  Come on, I can think up ten better pranks than that before breakfast.  A hundred if I had a selkie skin to use."

By the Sea Witch, he knew what he had.  This was much worse than she thought.  He'd know better than to be bought off with fairy gold, then.

"What do you want for it?  Your sister can have these shorts and sandals in exchange for the loan of the swimsuit.  And you can apologize to her on my behalf."

"Not like she'd believe me, anyway.  She can keep guessing about where her swimsuit went all day.  No, on second thought, I think I'll just borrow your skin for a while.  An hour or two, that's all."  He looked up and down the beach; they weren't completely alone, but nobody was nearby or paying them much attention.

"What do you want to do with it?" she asked.  "If it gets damaged --"

"I just want to go for a swim," he said, and started to wrap himself in it.

"No!" she shouted, and he paused.  "That's -- it's a very bad idea.  I don't know what would happen if you put it on while you're naked; it probably won't be good for either of us... but I *do* know that you'd kill yourself and destroy the skin if you put it on over that swimsuit."

"Easy enough," he said.  "You can turn your back if you like," and he stripped out of his swimming shorts.  She didn't turn her back; she hadn't seen a mortal man naked, even a young scrawny one like this, in a decade or more, the last time she came on shore in human form.  Her flirtations today hadn't worked out.  The boy wrapped the skin around himself and it first stretched to cover him, then he shrank to fit it... and moments later a seal sat there.  She looked at herself, nuzzling her flippers and hindquarters, and then waddled off toward the water.

"Come back soon," the selkie called out desperately.  "Don't stay out too long."  She sat down on the wooden steps and looked out to sea, her fate hanging in the balance.

Half an hour later, a middle-aged woman came out of the beach house and called: "Jason, where are you?  Come on in, we're going to play Parcheesi."  Getting no answer, she came down the walkway and steps across the dunes and paused in surprise to see the selkie sitting there.

"Excuse me," she said, "these are private steps."

"No problem, I'll just move," the selkie said, and got up, sitting down a moment later a few yards down the beach.

The older woman walked out onto the beach, looked around, and frowned.  "Jason!" she called even louder.  "Where are you?"  She turned to the selkie and asked, "Have you seen my son?  He's fourteen, about five foot seven with brown hair... he needs a haircut."

"Yeah, I think I passed him coming south, a few minutes ago.  He was walking up toward the pier with a couple of other guys his age."  She hoped Jason appreciated the alibi she was giving him.

The older woman grumbled and went back inside.  The selkie continued to sit and wait for the boy with her skin to return.

Finally, after everyone in sight had gone into their houses and it had been ten minutes since the last time someone walking along the beach passed her, a seal came swimming up to shore and onto the beach.  She barked a couple of times and waddled over toward the selkie, who sprang up and walked toward her.

"You don't know how to get out of the skin, do you?" she asked, and the seal shook its head. "Then let me help you.  Stretch your flippers to follow the motions of my hands," and she put her hands on the seal's forelimbs and guided them through a complex series of motions.  After three attempts, the skin split down the front and a human spilled out.

But not the fourteen-year-old boy who had stolen her skin.  A girl of about the same age lay sprawled on the beach.  She rolled over and squawked.

"I'm a girl!  Why am I a girl?"

"How should I know?" the selkie asked.  "I told you I didn't know what would happen if you wore my skin.  But probably because you wore a female seal's skin." She took the sealskin back, then stripped off her sandals, shorts and swimsuit and tosssed them at the girl.  "Goodbye."  She got back into her skin and headed into the sea.

"Wait!" the girl cried.  "I don't know how to -- I can't -- You can't leave me like this!"

But the seal swam off to the south, making no answer.