First of all, she's been recruited by a mystical clan called the Spider Society to be their "Hunter" and to fight to preserve the peace of the world.
Second, nobody really believes she's the right one for the job — except for the society's mage, Miguel. It was he who chose her to be his partner, endowing her with the ritual marking that supposedly activated dormant powers she didn't even know she had.
Third, the ritual marking is a spider-shaped tattoo — which her dad will totally freak over if he sees! And she has to lie to him and tell him she's an intern for the Spider Society's front company, WebCorps.
Fourth, she hasn't really developed any powers yet! Although her new tattoo has been acting really weird lately...
Fifth, Anya's first unofficial assignment for WebCorps was a huge Mess! She almost botched a rescue job to recover Miguel from the Sisterhood of the Wasp, the sworn enemies of the Spider Society. It's a good thing she had help from WebCorps' resident hacker, Ted, and an aspiring executive named Nina (who gets really catty around Anya, by the way).
Sixth, Miguel wants to send her on something called The Trials, to see if she truly is the rightful Initiate.
Seventh, nobody at WebCorps is sure she'll survive. Not even Miguel.
Eighth, you did read number seven, right?