Cursed to be a siren, Gemma's life is slowly being destroyed. Struggling to move away from the savage darkness she needs to survive, she's desperate to break the curse that has turned her into a monster and is keeping her from the family — and boy — that she loves. But the alluring yet lethal sirens, Penn, Thea and the newly initiated, Liv have no intention of letting her go. The key to her freedom lies with an ancient scroll and Gemma's frantic search leads her to someone who might be able to help—the mysterious immortal Diana, who cursed Penn and her sisters thousands of years ago. But Diana will not give up her secrets easily and unless Gemma and her sister Harper can unlock the scroll's powers then Penn will trap Harper's boyfriend Daniel and destroy the two sisters for good.