Charlie Hart is a freshly graduated engineer with a healthy lack of respect for No Entry signs. Her biggest problems in life are workplace misogyny, student debts, and the illegality of her urban exploration hobby. But when her whole family is kidnapped right out of the heart of London, her world is flipped upside down by the suave asshole of a spy whose job it is to get them back.

Charlie is drawn into a world of misfits and irregulars working for an intelligence agency that doesn't officially exist. The Special Operations Executive was consigned to history's rubbish bin in 1946, and so far as most people know it stayed there. Now it's Charlie's only hope of rescuing her family from the megalomaniac billionaire who has taken them from her.

And it turns out he's got a nuclear arsenal that he really wants to use.