Witness

Humanity forgot the hidden world, but it hasn't forgotten humanity.
In Witness, Laura Collins is violently pulled into its secrets. As prominent figures turn up dead, their life force stolen, she is plagued by disturbing memory gaps and whispers that hint at an ancient enemy's return.
Her only hope lies in finding her missing fiancé, Ethan, and piecing together the clues only she seems to possess. But the truth leads not just to a centuries-old war, but to something awakening within her-a power that may be humanity's salvation... or the enemy's greatest weapon.