'Watch out for the seaponies.'
Those had been the last words Guiding Light said to him before the old stallion passed his duties on to Beacon Heart. 'Watch out for the seaponies.'
Beacon had just chuckled at the time, believing it to be a joke. Or perhaps the loneliness and isolation of his posting had caused the old stallion to see things? He might have been young, but he was no foal, believing in old mare's tales like mermares and manticores. Nor did he believe that a little isolation would bother a tough earth pony such as himself much.
When the pegasi drawn carriage departed, Beacon was left alone at his new posting. He took a few moments to look around the small rocky island that would now be his home and workplace. He closed his eyes and took a deep breath, filling his lungs with salty sea air and his soul with determination.
This was his first posting, and he would not fail in his duties. There was work to be done.
A little bit of isolation wouldn't bother him at all.
The bad lands were a strange place for a lighthouse.
Or so most ponies would say.
Ponies thought of the Badlands as hundreds of miles of desert and scrub brush. Nopony gave much thought to the ocean that lay on the other side. Nopony but the sailors that passed the treacherous coastline as they carried trade goods between Zebrica and Equestria.
There were no towns or villages here. No pegasi weather teams to disperse storms or bust clouds. The ships that passed the Badlands passed through rough, wild weather and stormy, dangerous seas.
Those ships needed a lighthouse to warn them and guide them to safety.
And a lighthouse needs a lighthouse keeper.
Time proved Beacon Heart a fool. A fool twice over.
Firstly, because it was lonely enough on his little island to drive a pony to hallucinations. The biweekly pegasi supply runs provided him with fresh food and news, but little conversation. The loneliness was almost unbearable.
Secondly, because the seaponies were real.
Strange, skittish creatures they were. Earth ponies from the flank up, and naught but fish scales and strange, graceful tails below.
Sometimes they would sun themselves on the rocks around his lighthouse. They seemed to enjoy the sheltered waters of a particular small, rocky grotto.
At first he kept his distance. The mermares seemed to have the same idea, as they would dive into the deep waters of the grotto whenever his duties forced him to draw near.
But eventually loneliness got the best of him. As strange and worrisome as he found the creatures, they were somepony to talk to. And as skittish and flighty as they were, they eventually grew comfortable with his presence.
One seapony in particular was braver than most. Sea Foam was her name, and she found the workings of the lighthouse, and its keepers, fascinating. She had lived her whole life in the ocean around his tiny island, and spent every night watching the bright beams of the lighthouse cut through the darkness.
Beacon Heart and Sea Foam spoke of many things. The workings of the lighthouse. The wrecks of ancient ships she found in the depths. The strange things found far inland, or deep in the sea.
They gave each other gifts. Small things. A fresh orange, or a bit of sea glass. A silvered mirror, or a shark's tooth. Bits and baubles from two separate worlds.
Over time they learned much about each other. Peculiar little customs and amusing turns of phrase. Truths that were universal across ponykind and quirks and foibles that were unique to each of them. Small secrets, embarrassing moments and silly dreams, no longer hidden away but entrusted to one another.
And Beacon learned that his lighthouse did more than just warn ships away from the dangerous shoals. To the mermares it was a light guiding them back home. Guiding them to safety.
Time passed, and so did Beacon's loneliness.
Time passed.
Days turned into weeks, turned into months, turned into years.
Occasional visits to the grotto turned into regular visits. Turned into every sunny afternoon. Turned into every day it wasn't storming.
'That strange mermare' turned into 'That strange mare.'
Turned into 'That nice mare.'
Turned into 'That pretty mare'
Turned into 'That beautiful mare with the turquoise eyes you could lose yourself in, orange mane like the setting sun, and lips as red at the most delicious rose.'
Time passed. And after three years, Beacon Heart's calendar had reached its final days.
His rotation was over. He would return to the lands of his birth, and a new lighthouse keeper would take over his duties, as he had taken over from Guiding Light.
The pegasi drawn carriage would arrive with his replacement soon. His final duty was to pass on his knowledge and experience to his successor, as Guiding Light had done for him. He made sure to leave detailed notes and written instructions inside the lighthouse.
He wouldn't be there to speak to them in person.
Watch out for the seaponies Guiding Light had said.
Not 'Beware the seaponies.' or 'Stay away from the seaponies.'
'Watch out for the seaponies.'
For three years he'd done just that. And now somepony else would come to care for the lighthouse.
But watching out for the seaponies was a duty he could not give up and pass on.
Not when there was one seapony that Beacon Heart wanted to watch forever.
Beacon Heart stood upon the rocks of the grotto, looking down at Sea Foam.
The water here was deep. If he jumped, his hooves might never touch the bottom.
If he jumped, his hooves might never touch dry land again.
He was afraid.
He looked into her eyes, and they spoke to him. They said I love you and I will keep you safe.
He closed his eyes, taking one last deep breath.
His lungs were filled with salty air, his heart with love and determination.
Four hooves left the rocks of the grotto.
Two hooves and a tail struck the water below.
The ocean closed over his head with nary a splash.
Author's Note
This story was written for June 2016 Write-Off Event: In Over Your Head. At the time I decided to write in a genre that is somewhat outside my skill set: Romance. Furthermore, I decided to write a story with zero dialogue, because that seemed to work well for me in the past for some reason.
Apparently the combination worked out, because I took first place, and won my first medal!
As an aside, I should note that after turning into a sea pony, Beacon Heart and Sea Foam were married, had a whole school of happy little colts and fillies, grew old together, and eventually swam off to explore the deep ocean in their dotage. Because in a happy fairytale nobody dies on screen, not even of old age. 
I say all this because a popular interpretation of my story was that Sea Foam drowned poor Beacon Heart, because that's what sea ponies do. 
So, my attempts at a romance story are easily mistaken for a dark, twisted tale of homicide. And my dialogue is so bad that my stories do best when I leave it out. Either my writing needs a lot of work, or my audience is insane. Possibly both. 
But hey, this still won a gold medal! So yay! 
