Eleven-year-old Dawn Buckle, with her nondescript appearance and mushroom-colored knee socks, is constantly ignored and overlooked—even by her own parents. This natural knack for invisibility, while personally frustrating, pays off when Dawn is recruited by an English spy-busting organization known as P.S.S.T. (Pursuit of Scheming Spies and Traitors), a division of S.H.H. (Strictly Hush-Hush). Dawn’s assigned mission is to go undercover as Kitty Wilson, infiltrating an Essex village in pursuit of the missing Angela Bradshaw, a spy at P.S.S.T. for 40 years who may have been captured by the villainous traitor Murdo Meek. While genuine danger looms, silliness trumps all in this giddy novel, complete with torturing turtles, secret staircases, magpie messengers and a school of red herrings. Readers will not care so much about the dizzying dénouement as revel in the details of the hunt and the tools of the trade (like a shell-shaped telephone and disappearing purple ink). Amid the madcap spy antics is the story of a once-invisible girl who happily loses her knack for going unnoticed. (Fiction. 9-12)