Lost in time and considered a myth, it is said that The Mermaid's Heart, a massive sapphire, holds mystical powers and was created by Zeus himself. The powers that legend has attached to the Mermaid's Heart, are said to be boundless, granting the one who holds it their fondest wishes and eternal life. When Carly Harden was a little girl, her grandmother told her a story about a mermaid named Sapphire. Adding to the mystique, Granny Harden gave her a small gold key that Carly still wears on a chain. It's her good luck charm. Carly has worked at The Blue Mermaid for three years . . . and has been in love with her boss, Tony Sargento, the entire time. She's also known who and what Team Nightly really is and that Tony is uccisore.Now that she has revealed to the elite team of vampire slayers that she knows their secret Tony is furious with her. Adding that Carly's best friend, Scarlett James and her twin brother, Rhett, are the newest additions to the team, Tony can't help but wonder if Carly and Rhett are more than just friends, adding more fuel to their tumultuous relationship. As the tension between them stretches the boundaries of their friendship, neither of them realize the danger that Carly is really in Until Gordon Charles, Vampire King, sends his minions after her and Carly is nearly killed. Tony and Rhett set aside their animosity to protect her. As they dig deeper into the family legend around Carly's key, they realize that the three keys that unlock the chest holding The Mermaid's Heart is what Gordon Charles is really after. Gordon has already obtained one of the lost keys. Carly's key is the second. If he finds the remaining key and takes possession of The Mermaid's Heart before Team Nightly can get to it, the Vampire King will be the one to obtain his heart's desires: To walk in the sunlight once more, kill all uccisori and create his own vampire utopia where humans are nothing more than a food source.