When her father beheaded her mother, Princess Elowyn Blackthorn was stripped of her titles and banished for twenty years. Summoned back to court, she dares to hope it’s a second chance. Instead, she’s tricked into a betrothal to a man she despises.

Her life is over—until her ship is seized by sirens.

In Naiadon, the castle beneath the sea, the sirens believe Elowyn is the key to uncovering the truth behind their vanishing kin and to winning the war they plan to wage on her homeland. Though held captive, Elowyn grapples with her loyalty to the kingdom that betrayed her and her growing connection to the ocean’s mysterious inhabitants.

Her only ally is fellow prisoner Captain Arlo—maddeningly handsome and fiercely determined to free his captured crew. As they plot their escape, both suppress their attraction to one another, knowing distraction could cost them their freedom. But while Elowyn begins to see the sirens as something more than monsters, Arlo sees only captors.

As tensions rise above and below the sea, Elowyn must decide where her loyalty lies: with the man she’s falling for, the realm that forgot her, or the sirens who offer her not just freedom, but power.