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.

She had been told what to do her entire life, she was abandoned and left alone. Who was the cause of her pain and suffering? The one and only Joker. Now she had to take away anything that he had ever worked for and that includes killing his nemesis Batman.