Marza Hines doesn't know she has a twin sister. That is until she appears out of nowhere trying to kill her. That night, Marza learns not only of her sister Jen, but also the truth about herself. Marza is immortal. The only way she can die is at the hands of her long-lost sister. The curse requires that one of them succeed in killing the other by their 18th birthday. If not, they will both die. Marza and Jen aren't the only ones, and now it's up to her to help those who can't help themselves.