Spy Society: Disguised and Dangerous by Jane Mason (author) (US edition)

Giggles, friendship and spy missions… perfect if you love The Famous Five or Clarice Bean. When four girlfriends start their own brand new Spy Society, they’re primed for adventure. And it’s not long before a mystery comes their way. But can these girls solve their first case and remain best friends to the end? And are their disguises and gadgets smart enough to catch real-life crooks? Awesomely exciting.