Madeline Glover 
The Bioluminescent Conductor [EPUB ebook] 
Symphony of the Deep

2247. The surface world is lost, swallowed by the rising tides.  Humanity clings to life in Aquatica, a shimmering underwater metropolis, its fate intertwined with the bioluminescent coral that powers their submerged world. But the coral is dying, strangled by a mysterious blight, and darkness threatens to consume them all.
Elias Vance, a disgraced train conductor haunted by a past tragedy, is offered a perilous chance at redemption. Lucian Thorne, a ruthless corporate magnate, tasks him with leading an expedition into the unexplored Abyssal Trench, a realm of crushing pressures and perpetual night, to find a rumored strain of blight-resistant coral.  But Elias suspects Thorne’s motives are far more sinister than salvation.
Aboard the rebuilt *Cerulean Serpent*, Elias descends into the abyss with a crew of fractured souls: Dr. Iris Bellweather, a brilliant marine biologist driven by personal loss; Silas Finch, a veteran diver haunted by the ghosts of the deep; and Anya Sharma, a young engineer whose idealism hasn’t yet been drowned by the harsh realities of their world.
In the heart of the Trench, they discover an impossible garden of bioluminescent flora, and encounter the Eternals—beings of pure light, remnants of an ancient civilization.  They speak in a mesmerizing language of bioluminescence, a symphony of light that reveals a terrifying truth: the blight is not a disease, but a desperate cry from the ocean itself, a reaction to humanity’s relentless exploitation.
Elias is torn. Obey Thorne and potentially save Aquatica, or heed the Eternals’ warning and risk condemning his city to darkness.  As the *Cerulean Serpent* pushes deeper, strange phenomena begin to manifest, mirroring the growing tension within the crew.  Elias uncovers evidence of Thorne’s deceit, revealing a conspiracy that threatens not only Aquatica, but the delicate balance of the entire ocean.
A mutiny erupts. A desperate chase ensues.  Amidst the breathtaking beauty of the Abyssal Trench, a battle for the soul of the ocean unfolds, a dazzling spectacle of light and shadow, of technology clashing with the raw power of the deep.  The fate of Aquatica, and perhaps all of humanity, rests on the crew of the *Cerulean Serpent*, and their ability to decipher the silent symphony of the deep.