A princess disguises herself as a captain to avenge the death of her brother and eradicate the sirens that plague their waters.
A siren warrior, banished for the death of a princess, becomes human with the help of a sea witch in order to bring the princess back to life.
Both on opposing sides, the two never expect to fall for each other.
Not all happily-ever-afters last forever.
The day before Kae and Aqeara's royal wedding, a random attack on Avalon's port leaves the kingdom reeling with loss. The two queens learn of similar attacks in other kingdoms, including Aqeara's underwater home.
On a mission to hunt the individuals behind the attacks, Queen Kae and Queen Aqeara replace their crowns for tricorn hats and blades. They rally their crew and set sail on a dangerous adventure where secrets swirl to life and truths threaten to overcome them.