Huntress Ro LeFèvre is hired to hunt the sirens who have been sinking the king of Angleterre's ships, and in turn, vast amounts of his wealth. All who have gone before her have failed.

Fleeing heartbreak, Ro gladly accepts, but there's just one problem. The king will credit the Marquis de la Valère, and no other women are allowed on the voyage.

Ro will just see about that.

Hiring an all-female pirate crew without the king's knowledge, Ro hopes they will follow her to the Caribbean, not take the gold and flee.

But when Ro is plunged deep into the ocean by the siren she's being paid to kill, presented the sirens' side of the story at knife point, and pressed to join them or die, Ro must decide whether to complete her mission, join the sirens, or something in between.

Before the sirens sink the ship full of men above.