Amy Cahill was horrified to discover that there was a traitor in the Cahill organization. But there's no time for her to grieve about the betrayal. The mole has been feeding crucial information to the Vespers, and carrying out their orders. Amy and Dan have managed to stay safe for now, but there's no telling what Vesper One will have the mole do next. You know what they say: Keep your friends close...unless they're working for a murderous psychopath.