I couldn't put this book down! Great story with lots of twists and turns. If you like stories about adventure, this is the one for you. But be warned: There is quite a lot of gun violence.

This book was so awesome! I can’t stress that enough. Charlie is a 12 year old genius and she has is working with the CIA to find one of Einstein’s equations that could be very dangerous in the wrong hands.If you liked Stuart Gibbs Spy School you would love this book

This book is about a strong, brave, and intelligent young woman. Charlie is a 12 year old who has a amazing IQ (maybe even better than Einstein). She works with her half brother and another CIA agent to get Einstein's last equation before the other counties, and furies.

it was bad at the beginning good in the middle bad in the end and it was just OK..........so ya

before I read this book I wasn't interested in mysteries. now that I read this book I have a change in thought......... /_('u')_/