Fracture (Night School #3) by C.J. Daugherty

Devastated by the loss of her friend and under constant threat from an unknown spy at Cimmeria Academy, Allie Sheridan is finding it hard to cope.

In Fracture, the third book in the Night School series, she’s not the only one losing it – everything is falling apart. And when Nathaniel begins to reveal his game plan, Isabelle starts to lose control.