Fenna Vos has learned to focus on her own survival—even now, with the Second World War raging in faraway countries. She works on-stage as the assistant to an unruly escape artist—behind the curtain as the mastermind of their act. After all, her honed ability to control her surroundings and elude entrapments, physical or otherwise, reliably suppresses the trauma and tragedy of her youth. For all her calculations, however, Fenna neglects to foresee being called upon by British Intelligence. Tasked with creating escape tools to thwart the Germans, MI9 seeks those with specialized skills for a war nearing its breaking point. Fenna reluctantly joins an unconventional group of inventors—but delving deeper into the fray means a confrontation with her past and stakes more treacherous than she ever imagined.