Simon & Schuster have put these three books into a handy single volume. Debuted as #1 on the New York Times Bestseller List.

The Strange Power:  (New York Times Bestseller!)
Is the first book in the trilogy. In this we first see Kaitlyn Fairchild: the resident witch in her school. Kait doesn’t deliberately practice witchcraft, but every so often she gets the urge to draw. The problem is that the pictures are mysterious and macabre . . . and they always end up coming true before Kaitlyn can figure out what they mean. Given the chance to transfer to the Zetes Institute, a small boardinghouse school populated only by teens like Kait, with strange powers, Kaitlyn jumps at the chance. But neither the Institute nor Dr. Zetes is what they seem . . .

The Possessed:  (New York Times Bestseller!)
Having discovered what Dr. Zetes really wants them for—and what happened to their predecessors at the Institute, Kaitlyn and her friends Anna, Lewis, Rob, and Gabriel have to run for their lives. In doing so, Kaitlyn discovers that Gabriel is a vampire—but that he feeds directly on human life-energy. Kait is caught between golden Rob, the healer, and wicked Gabriel Wolfe, who may just be using her for his own purposes.

The Passion: (New York Times Bestseller!)
Finally having found a weapon with which to fight Dr. Zetes, Kaitlyn and the others return to the Zetes Institute. But no one is ever exactly what they seem, and the triple-twist ending of the book has one of Kait’s suitors backing off, seeing the passion she shares with the other.