A/N: Just a thing I wrote for Jily Pirate Fest on tumblr c: (by the way, if you happen to have a tumblr, check out the tag 'jily pirate fest'. It's really fab!). *dramatic flourish* I present to you, Cutthroats and Sirens!

The four men stood on the deck, looking out towards the darkening horizon. The water around them lapped gently at the sides of the ship, and a gentle, salty breeze danced around their faces. It was the perfect weather for an ambush, but the concern and gravity on their faces would not have implied so. Their gazes were all trained on a nearby rock outcrop, jutting out of the placid sea like an ugly tooth. It seemed very out of place in the vast stretch of blueness. To make things worse, they could make out the vague outline of a human hunched atop it.

"Well," Captain James Potter said, "that can't be a good sign."

"Wonderfully put, Captain," muttered Sirius Black, his first mate. Sirius's propensity for sarcasm increased with the direness of the situation, and for the past few minutes, his words had been practically soaked in it. "Any other eye-opening statements you've got in that noggin of yours?"

James scowled, turning instead to Remus Lupin. He, at least, could be counted on in situations like this. "What should we do?"

Remus shrugged helplessly. "Er - I'd say avoid it at all costs?"

"The wind's blowing us in that direction," said Peter Pettigrew.

"This is hardly what you'd call wind-" Sirius broke off as a sudden gust pushed them ominously closer to the rock. He swore loudly.

"Definitely not a good sign," James clarified. "Right, we've got to make sure none of the crew see this, they'll lose their minds. Moony, Wormtail, run distraction."

"On the entire crew?" Peter protested.

"That's an order," James said, simply because he liked the way those words sounded. Turning his attention back to the rock, he pulled out a telescope and peered through it. The blurred figure became sharper, and James saw long, red hair, rippling like flames in the wind. The wind pushed them closer and closer until he could make out torn clothes and porcelain skin. He cursed, and Sirius grabbed the telescope from him.

"It can't be - some sort of omen?" he half-asked.

Sirius shook his head slowly. "James - look again. It's not a siren, it's a girl."

"It's a what?!" James snatched the telescope back, and squinted through it again. Sirius was right; the figure might've been quite the looker, but not the kind of inhuman beauty sirens were said to have. The girl was dressed like a boy, in a shirt and breeches, and hunched on the rock. He wondered how long she'd been there, and how cold she must be. "We've got to-"

"We can't bring a girl onto the ship!" Sirius hissed. "The crew-"

"Fuck the crew! Look at her, Sirius! She must be freezing out there!"

"It's a bad omen to have a lady on a ship," Sirius said stubbornly.

"I always seem to have luck on my side," retorted James. Sirius shook his head, but did not argue. James strode up to the bow, shouting, "Starboard! To starboard!" The ship eased slowly to the right, the wind miraculously dying down until the massive vessel came to a complete stop. James knew that shouldn't have happened; it was almost physically impossible to be stationary in open water, but he pushed the worries from his mind and hurried towards the rock.

The girl was standing now, staring up at the black flag hoisted high above James's ship. He could see her lips form the word 'pirate', her eyes wide. Then she caught sight of him. She stiffened, her gaze becoming steely.

"Are you going to rescue me, or rob me?" she said.

James blinked. "Rescue," he called back.

"Never trust a pirate," came her reply.

"You've got a lot of nerve for someone stranded on a rock in the middle of nowhere!" he said. She shrugged. Shaking his head, James said, "I'll come get you."

"Not likely. Throw down a rope, I'll swim up to your ship."

This girl was getting more interesting by the minute, James thought. A few minutes later, when she was standing on his ship, soaking wet, he corrected himself. This woman was getting more interesting by the minute.

"Stop staring at me," she said bluntly. He immediately averted his eyes, and then cursed himself for his stupidity. "What's this, a chivalrous pirate?" she chuckled. He loved the sound. It was dry, hoarse, throaty, like the slap of a gentle wave.

"Chivalry's dead around these parts," he muttered. It was true; if anyone else had found her, marooned on a rock…

"Lovely to know that I've made my way onto the good sort of pirate ship," she said dryly.

"Is there really any such thing?"

"You tell me, Captain." She took a step towards him, her green eyes flashing. "Are you some sort of mad cutthroat?"

"Are you a siren?" he countered.

"Not nearly beautiful enough."

"And I'm not nearly mad enough."

She smiled. "That remains to be seen." She turned away from him and peered at the water, humming under her breath.

"What's your name?" James asked eventually, after he'd managed to tear his eyes from her face and allow his mind time to formulate a question.

"Lily," she said after a moment's hesitation.

"Captain James Potter." He wanted to ask about her surname, but he held his tongue. Lily nodded slowly, chewing on her lip. "So, where should we drop you off?"

"You're letting me stay?" she said, incredulous.

"Yes, well, I can't very well toss you off my ship, can I?"

"Theoretically, yes, you could."

James waved her statement away. "We'll just have to make sure the crew doesn't see you. Bad luck to-"

"-sail with a woman," she finished. "I know. Hopefully I won't be with you for too long."

James did not share her hopes, but decided against voicing his thoughts. "You've very nice eyes," he blurted out.

"Excuse me?" For the first time, she sounded like he'd caught her off guard.

"Nice - eyes," James repeated, wishing he could fling himself into the sea. "They're a very nice shade of-" He broke off, staring at her intently. He could've sworn…

"What?" she said, sounding uneasy.

"Nothing. Your eyes were green before, but they look blue now."

Lily blinked, and her eyes returned to their normal colour. "Must've been a trick of the light."

"Must've been."

They stood in silence for some time, Lily's humming getting all the while louder. Her voice was surprisingly melodious, sweet where her laughter had been coarse. James tried to identify the tune, but he'd never heard it before. She began to whisper the words, the sound of the waves blocking her voice out momentarily. James glanced back at her eyes.

Blue. Blue as the water's surface.

He wanted to hit himself for being so stupid. He opened his mouth to speak, tried to move, but something was holding him in place - her words, her song, her magic. She grinned cheekily at his horrified expression, laughing again. It sounded as though the water itself was laughing. 'Siren', he managed to mouth.

"Here's a tip for you, Captain," she said. "When you get to Davy Jones's locker, you can tell everyone this story. And remember to tell them all that sirens lie."

Then, to his surprise, she pressed her lips to his, momentarily freeing his limbs. Her body was flush against his, her arms twined around his neck. He returned the kiss with feeling, knotting his fingers in her red, red hair. And all too soon, she pulled away and leaped over the edge of the ship. Dizzy and shaken, all that James registered was the taste of her lips. She had tasted salty, like sea-spray. Then, everything went black.

The first thing James did when he woke was cough. Someone pounded on his back, and seawater poured from his mouth. His throat felt dry, and when he spoke, his voice was a harsh rasp. "What - happened?" The faces around him slowly became recognisable. Sirius, Remus, and Peter were looking down at him, relief written on their faces. They were in a small unfamiliar room - an inn, he guessed.

"Freak storm," Sirius replied darkly. "It's a miracle we even survived it."

"Crew?" James asked.

"Most of them are all right, they're here with us. We've lost a couple, and…" Remus hesitated.

"And what?"

"And the girl," Sirius said. "We never found her. She's probably still stranded out there."

"Oh," James managed, his voice strained. "It was a miracle we survived, you said?"

"Yes, we were headed straight for rocks, dozens of them." Peter shuddered. "We should've died."

Remus nodded solemnly. "Miracle doesn't even begin to describe it."

Numb, James staggered to his feet and walked to the window. He brushed the grains of salt from his skin, and his fingers closed around a long strand of hair. Holding it up to the light, he could see that it was coppery-red. The sun was rising in a blaze of crimson outside, the sea looking for a moment like blood. And he was certain it was no coincidence, this miracle.