A/N: This fic is a long overdue gift for my dear friend, Nocturnias. Part 2 is in the works and I hope to have it all finished before her birthday. I hope you enjoy it!

Prompt: AU obviously. Rated E please. Molly living in a lighthouse for a summer, Sherlock the merman washes ashore during a storm. The rest is at your discretion but please a happy ending!


He's beautiful, even unconscious, bruised and bleeding. That's her first thought.

Her second thought is that he isn't nearly as heavy as a water-logged, near drowning victim should be, although she attributes that partially to the fact that he's shirtless, his swimmer's shoulders and pale flesh suggesting contradictory facts - surely anyone who spent enough time in the water to develop that distinctive muscular pattern would have an equally well developed tan?

Her third thought is impossible to decipher as it involves deep consternation, astonishment, fear, frank disbelief, and every other conceivable emotion as she pulls him clear enough of the crashing waves to see his full body.

He doesn't have legs. Below the waist, starting in a v-pattern from his hips, he has the body of a fish. A fish's tail, covered in iridescent blue/green scales with the faintest flecks of amber scattered here and there, almost glowing in the light of the setting sun…

Her mind goes blank at the impossibility of what she's seeing, and she nearly drops him.

He's a merman.

It's not a costume; she can see where the flesh of his torso merges seamlessly into the iridescent scales; can tell immediately, student of anatomy as she is, that there are no legs hidden inside. No obvious bumps and lines where knees, thighs, calves, ankles, feet would be...

Molly Hooper's storm-damaged victim isn't human, and her summer as a lighthouse keeper has just become immeasurably more complex than she could have ever imagined.

She stands there, frozen in shock, the icy seawater ebbing and flowing around her ankles, her bare feet sinking into the sand, every nerve in her body screaming at her to flee, to lock herself into the lighthouse and call for help.

His eyes flicker open. They are the same iridescent blue/green with the faintest flecks of (softly glowing) amber as his scales. He chokes, coughs; water fountains from his mouth and her emergency medical training kicks in. She drags him the final meter away from the reach of the waves (does he need to remain immersed, should she worry about the sea-creature half of his nature, no, focus on the man who is clearly in respiratory distress, his lungs not entirely cleared of water).

She lays him on the sand. Rolls him to the side as he continues to cough and choke and helps him expel the last of the water clogging his lungs. Watches carefully for signs that he needs any other assistance. The gash on his head is still bleeding sluggishly, but experience tells her it's nothing that a bandage can't handle, and as for the bruises, they look superficial enough to be allowed to heal on their own.

She hopes.

Still coughing, he pushes himself up on his arms into what she would call a sitting position had he been in actual possession of a bum on which to sit. His tail curls and straightens and his eyes meet hers again. His mouth opens, and Molly unconsciously leans closer, fascinated to hear his voice, to learn what language a merman speaks.

His words are both unexpected and unpleasant. "Who the hell are you?" he demands angrily. In perfect, poshly accented English.

The deep baritone rumble of his voice would be beautiful if his words weren't so peevish - not to mention, ungrateful.

"I'm Molly Hooper," she manages after a moment, meeting his scowl with one of her own. "I'm the person who rescued you from drowning!"

"I'm of the Mer, we don't drown," he scoffs, then coughs and spits out one last trickle of water, belying his own words. His scowl deepens, and he presses his hands to his chest, to the sides of his neck, and she sees something like panic in his eyes. "Shit! This can't be happening, not now of all times!"

"What is it? What do you need?" Molly asks, reacting with instinctive empathy to the growing panic in his voice. No matter how ungracious his first words might have been, it's obvious that he needs her help. Or, if not hers, then someone's help.

"What could I possibly need from you?" he sneers, turning his head away.

"Nothing," she mutters. "You could just say thank you."

She climbs to her feet, empathy turned to annoyance, ready to march back to the lighthouse, but his next words stop her. "Thank you."

She turns back, looks down at him in disbelief, then smiles tentatively. "You're welcome. Are, are you sure there isn't anything I can do to help? Anything you need?" She winces as she repeats her earlier question, but his expression is resigned rather than annoyed as he responds, a single word that sends her reeling.

"You."

oOo

Shit. Shit, shit, SHIT. This can NOT be happening. Not now, when he's in the middle of his explorations of the coastal waters of this Drylander island! His Work, his mapping of the world above the waves, is not even half-way completed, and to be interrupted by a mere quirk of Mer biology-? "NO!" he exclaims, startling the human woman standing above him.

She skips back a step. "No?" she echoes uncertainly, before frowning down at him. "Well, which is it? Do you, you need me for something or not?"

"Yes I do, but no I don't want to," he snaps, then lets out a yelp of pain as the lower half of his body uncurls, straightening to its fullest extent. The woman - Molly - lets out an exclamation of surprise (sympathy?) and drops back to her knees, her hands hovering above his waist as she starts asking him anxious questions he ignores.

He collapses back onto the sand as another wave of pain washes over him, his back arching and a strangled gasp escaping his lips. He digs his fingers into the sand, eyes clenched shut, shuddering and shaking until suddenly he feels her hands on his shoulders, then the warmth of her body as she carefully rests his head and shoulders on her lap.

"What can I do?" she asks anxiously. "Should I call for a doctor? I don't want you to end up in some secret government lab being experimented on, but I don't want you to die, either!"

He responds to the real concern underlying the panic in her voice. "No...doctor," he manages to grind out. "Not...necessary. This is…" He shudders again as his body moves into the second phase of the Shift, stupid of him not to have realized that was what was happening! "It's just...biology. Natural," he gasps out, trying not to notice how comfortable her lap is, how soft her hands are against his cool flesh.

However, that proves to be impossible to ignore, as he feared. His body warms despite the chill in the air, growing feverish, and his thoughts narrow to one single, overpowering need: he turns in her embrace, reaches up, and pulls her down for a searing kiss.

As the kiss deepens, one last, tremendous shudder wracks his frame; a tearing sound rends the air, and he hears Molly cry out before the pain overcomes him and he passes back into unconsciousness.