After breathtaking adventures in France and Egypt, trusted Rosie Raja is put to the test among code breakers, double-crossers and resistance fighters in Bletchley Park, England, 1942. This time around, Rosie finds herself among the best and brightest codebreakers and spies – from Noor Inayat Khan to Alan Turing and the Hut 8 codebreakers themselves. While Gandhi’s Quit India movement is rising against the British Empire, Rosie and her spy father are working with British agents to keep the Nazis at bay. But with a rumoured Nazi spy working undercover at Bletchley park, who can Rosie trust? And when her father is put in serious danger, will she be able to save him?