Zero Hour:

Fate doesn't wait till your ready for it, it shows up and the most inconvenient time, knocks you flat and stands back to watch you struggle to get back up even though your feet are cemented to the ground with a little thing called reality. When Ally, the little ray of pure sunshine, arrives at her new school, it becomes apparent very soon, that her new home is far from normal. The only thing she has left from her old life is Seb, a tiny but genius level boy, but with Orion, the emotionless but good-natured outsider and Lyra, the sarcastic, self-assured fight picker, Ally is forced to enter the old military base on the out-skirts of town. Soon, two of the most popular people in the school, Toby, a privileged but unpredictable smart-ass and Mina a bombastic, confident flibbertigibbet are caught up in the mess surrounding them. But when this simple dare takes a running jump off the nearest cliff, these six teenagers realise that childhood problems are far from important. Along with Jinx, a street-performer who no one can figure out, they soon discover that a far more sinister problem is unfolding and it's up to them to figure out a way to stop it before the countdown finishes and Zero Hour arrives.