Sacrifice of the Brave King by Eliza Raine

The Poseidon Trials have never been more deadly, and it’s not just my life at stake. Poseidon, my sister, and the whole realm of Aquarius are just as likely to die as I am if we don’t stop Altas.
But the revelations coming my way are so much worse than anything the insane Titan can throw at me.
Between discovering the rest of the Oracle’s prophecy, what happened between Poseidon and Atlas’ wife, learning to use my magic, and trying to save my sister’s life, only one thing is certain.
If I fall in love with the fierce sea god, it will kill me as surely as the stone will.