The ocean is uncontrollable and dangerous. But to the sirens who swim the warm island waters, it's a home more than worth protecting from the humans and their steam-propelled ships. Between their hypnotic voices and the strength of their powerful tails, sirens have little to fear.

That is, until the ruthless pirate captain, Kian, creates a device to cancel out their songs.

Perle was the first siren captured, and while all since have either been sold or killed, Kian still keeps them prisoner. Though their song is muted and their tail paralyzed, Perle's hope for escape rekindles as another pirating vessel seizes Kian's ship. This new captain seems different, with his brilliant smile and his promises that Kian will never again be Perle's master. But he's still a human, and a captor in his own way. The compassion he and his rag-tag human family show can't be sincere... or can it?

Soon it becomes clear that Kian will hunt Perle relentlessly, taking down any siren in her path. As the tides turn, Perle must decide whether to run from Kian forever, or ride the forming wave into battle, hoping their newfound human companions will fight with them.