Where is Anybody?

"Gideon Sable specializes in stealing the kind of things that can't usually be stolen. But these days the legendary master thief is officially retired from the caper game. Now, instead of pulling off elaborate heists with his crew of supernatural specialists, he runs a magical shop in the heart of London with his partner Annie Anybody. Still, he can't resist occasionally going out in the night to steal things when Annie's not looking--for old times' sake, and for the joy of the con. But after one of his late-night illicit jaunts, Gideon returns to the shop to find that while he's been stealing, someone else has been hard at work--stealing from him. 'I have taken Annie Anybody, ' reads the note on the countertop. 'If you ever want to see her again, you must find and steal Time's Arrow. You have forty-eight hours'"--