The sea's siren song had seduced the mariner when he was still a wide-eyed lad. Her hypnotic susurrations promised adventure and freedom to any who dared to ride her waves. He set sail on a sturdy clipper ship his naive eyes bright with dreams. He never imagined how fully she would ravage him or how long she would keep him imprisoned with her suffocating embrace. After endless years lashed to her tempestuous will, his body was left a gnarled husk. His once strong hands were reduced to twisted claws by arthritis, his swollen knuckles protruding like warty growths. He clung desperately to the rotten railing, creaking, and popping in protest, keeping time with the pained groans of the termite-eaten timbers. His ship had become as broken-down and decrepit as he.  
The bitter sea winds sliced through his matted beard, sending errant wisps of gray dancing mockingly across his craggy face, now creased and spotted with the stains of age. His scraggly hair was but a wispy echo of the bold auburn mane he boasted in his prime. His rheumy eyes were clouded by thick cataracts he could see only muted impressions of the horizon. Seeing now was like trying to recall a vivid dream.   
Still, he forced the frigid air down his scarred lungs in ragged wheezing gasps. Each breath was a precarious balance just barely prolonging his withered body's slow dissolution into the black depths that threatened to swallow him whole.  
With trembling knotted hands, he tapped his oaken cane on the salt-encrusted planks, the tempo slow and halting. He would pause often, summoning his ebbing strength before rasping out a few mangled notes of slurred sea shanty. But the discordant sounds were devoured by the roaring abyssal waters. Yet he persisted in the damned ritual.   
When even this pale imitation of music failed him, only rhythmic splashing punctured the stillness, signaling his anticipated visitor had once again breached the surface. Blind, he could only follow the ripples with his shrouded eyes, straining to piece together her image from scattered memories echoing across the years. She always appeared just long enough to hear his fractured croaking, then vanished, leaving him to wonder what mystical siren could be so enthralled by his imperfect dirges.  
One night as the bloated sun sank slowly into the placid sea in a haze of bloodred, a question crawled up from his ruined throat and punctured the stillness: "Why do you never deign to sing back to me, friend?" Only his own trembling echoes greeted him...until finally her whispered words drifted up from the black depths - "I cannot..."  
Pity stirred his ancient heart, so long numbed by solitude. "You've no song of your own, my dear?" This time not even the mournful lapping waves responded, but he sensed her wordless confirmation in their gentle undulations. A stubborn resolve crystallized within his sagging frame then, to gift her the power of voice that had sustained his own marooned spirit all these long years.  
Each day he labored to coax some clumsy half-notes from her silent form, discordant yet beautiful in their raw primal authenticity. After countless sunrises and sunsets spanning into months into years, one gilded dusk her fractured siren's song finally rang out across the still waters - joyful reciprocation of the mariner's own broken shanty. A single tear carved its way down the mariner's weathered cheek at the haunting secret duet only they two shared in all the world.  
But even her song could not hold back time's crushing vice. As the mariner's ruined body failed him, her splashing ceased for good, leaving only a gaping silence more deafening than any storm's fury.  
In his final moments, as death clutched his withered frame in its icy grip, her distant call echoed once more across the abyss, a mournful song of sorrow deeper than the sea trenches. Then - oblivion claimed him at last.  
The siren breached in desperation, scouring the empty horizon for his battered craft. Endless inky swells mocked her, nothing left but his gnawed corpse tangled in the swaying kelp below - their haunting duet forever incomplete. She cried an earth-shattering song that spanned for miles across the churning waters. The ancient sea trembled, carrying the mariner's soul down to its lightless depths. The tide still shivered with the siren’s inconsolable lament.