To kill a kingdom

Princess Lira is siren royalty and the most lethal of them all until a twist of fate forces her to kill one of her own. As punishment, the Sea Queen transforms Lira into a human. Lira has until the winter solstice to deliver Prince Elian's heart to the Sea Queen or remain human forever. Prince Elian hunts sirens but when he rescues a drowning woman in the ocean, she's more than what she appears.