Slenderman Slayers

Everyone's heard of the Slenderman. "He" even has his own video game. But if there's evidence leading to it's existence dating back to before the Sphinx was created, why is it only now becoming noticed? Who's hidden him from the rest of the world? Who's kept the human race safe from such a creature? Ares, Blaze and Persephone have been a team for almost six years now, and they plan on adding a new member to the team, Dylan, but what happens when they get unexpected new member, Grace? And what happens when feelings get in the way, and she gets taken by the one thing she's supposed to be training to hunt?