What would you do if you were a thirteen-year-old kid and a secret agency asked you to become their ace code-cracker? Panic? Panic will freeze your brain. Tell all your friends? You'd be out on your ear Bozo! Could you keep it zipped? Well, could you, buster? Lucky for Ruby Redfort, she's not your average kid. She's never going to crack. She's super smart, she's always cool and she can keep her mouth shut - can't she? (Book flap).