Seventeen-year-old April Parker wakes up in an underground facility, a shock bracelet on her wrist and a five-day countdown on the clock. Dozens of other teens share her inexplicable fate, but their unseen captors never intervene no matter how brutal conditions become. When the ruthless - and unnervingly magnetic - Marcus seizes control, April's trauma-forged instinct is to lay low. But protecting her friends drives her to bargain with the boy she should fear most - a boy whose reality fractures with every tick. Then the countdown ends, and the real terror begins. Powers ignite. Alliances shatter. And predators are born. And with a saboteur among them determined to keep the doors closed forever, escaping what comes next may be the only way to survive it.

Despite the illusion Sapphire Dubois presents to the rest of the world, she is not just your stereotypical 22-year old Beverly Hills heiress; she hunts serial killers. While her fellow heirs spend their nights with trending celebs and drugs at the hottest club, Sapphire secretly spends hers luring, capturing, and anonymously handing over So-Cal's most wanted killers to the police - just your average Tuesday night. What Sapphire doesn't know is that one of her adversaries is watching her every move, aware of both her true identity and her unconventional hobby. Needless to say, he doesn't approve. Used to being the one who redefines the definition of predator and prey, Sapphire's world abruptly shatters when a gruesome 'gift' arrives for her at the Beverly Hills Country Club. With her involuntary crush, handsome Detective Aston Ridder, close on her tail, Sapphire now has to rethink her routine strategy and figure out how to capture a killer who already knows she's coming.