From award-winning author Alli Sinclair, comes a compelling story about tenacity and friendship, inspired by the real codebreaking women of Australia's top-secret Central Bureau in WWII

1943, Brisbane. The war continues to devastate and the battle for the Pacific threatens Australian shores. For Ellie O'Sullivan, helping the war effort means utilising her engineering skills for Qantas as they evacuate civilians and deliver supplies to armed forces overseas. Her exceptional logic and analytical skills attract the attention of Central Bureau, a highly-classified intelligence organisation working with England's Bletchley Park codebreakers. But joining Central Bureau means signing a lifetime secrecy contract. Breaking it is treason.

With her country's freedom at risk, Ellie works with a group of elite women who enter a world of volatile secrets, deciphering enemy communications and their work helps change the tide of the war. Tension escalates and Ellie's enforced secrecy strains her relationships to breaking point, especially when the man she loves presses for answers. She must find a way to protect both her mission and her heart.

As the war intensifies, the codebreaking women form a close bond. However, there could be a traitor in their midst. Can the women discover the double agent before their entire network collapses?