"Adra takes the helm of the [pirate ship] Worldeater after her half brother Cameron attacks their father and steals a priceless treasure map. Now, the young captain has only one desire: revenge. She will restore her father's honor by killing her brother, reclaiming the map he stole, and finding the legendary treasure at the grave of the first pirate king. But when Adra discovers her brother's ship destroyed and his crew dead--spare a sole survivor--she learns there's something lurking in the sea that's killing pirates, taking entire ships down with ease"-- Provided by publisher.