Half-human, half-vampire, Lillith Throne, also known as Twilight, was raised believing she had a purpose—to protect the human world. But everything changes when she meets Alaric Vale, the charming football captain who stirs feelings she was never meant to have. Falling for a human is forbidden, but resisting him is impossible.
When the truth of her bloodline is revealed, Lillith is thrust into a deadly war between the Shadow World and humanity. Her twin sister, Dawn, may be her greatest enemy. ...

Madeleine Cross -one of the few humans immune to the deadly virus Zion- after an unfortunate turn of events such as the loss of her last remaining parental figure finds herself captured by a BloodHound -a genetically enhanced being, designed to identify and retrieve the last remaining Negatives roaming the Earth.
She gets thrown into a sterile room to be subjected to various tests, under the pretence that her blood would be the key to develop an antidote against the deadly virus...But that could...