This novel by Simon Mawer is set in wartime Europe, when things are at their worst in France, and rationing has tightened its hold on England.
The situation is grim, and everyone who can is trying to assist the war effort.
This includes Marian Sutro, who joins the WAAF for a bit of excitement, then finds herself bored to sobs in a desk job in the English countryside.
But help is at hand. Sutro is recruited by the SOE (Special Operations Executive) to train as a spy. Sutro is a hybrid, half-French, half-English, and her fluency in both languages makes her an ideal candidate.
Oh, the excitement. The secrecy, the training in hand-to-hand combat, weaponry and sabotage, the false identities and code names - Mawer covers off the lot with authority and conviction. It's all a game at first. It gets serious when Sutro is parachuted into southwest France, ostensibly to act as a Resistance courier.
Her real mission is to get to Paris to make contact with old family friend Clement Pelletier, a nuclear physicist engaged in the race to create new and horrifying weapons.
His significance to the Allies is inestimable.
Mawer makes a pretty fair fist of exposing the conflicting moralities of nuclear fission, that Pandora's box of unknown outcomes resulting from genuine scientific research.
Who decides whether the possibilities of a nuclear explosion should be used for a quicker end to the war? How innocent are the scientists, and whose side are they on?
Our heroine struggles with this and questions of loyalty and betrayal as she alternately creeps, fights and blusters her way through the maze of accomplices and newfound friends.
The strain of weighing every word, of looking for hidden meanings and unexpected coincidences, of working out who is friend and who is foe, begins to take its toll.
Despite this, Marian Sutro is a convincing heroine. She's too smart for her own good at times, especially during training, but this attribute is essential later.
What completes her training is the understanding that war changes everything, and that love cannot be trusted.
Mawer adds to the suspense in this adventure by changing the tense of the book, from past to present, thus adding to the pace.
It's a nice trick and it works, although it's a little disconcerting at first.
The story ends suddenly and unexpectedly - to say more would ruin it.
Simon Mawer is an experienced and competent writer. His novel The Glass Room was shortlisted for the Man Booker in 2009, and he has written six other novels and two non-fiction works. His knowledge of physics and the intricacies of scientific research is impressive, although a little daunting at times.
In The Girl Who Fell From The Sky Mawer combines a gripping adventure story with a meditation on patriotism, love and betrayal.
It's a jolly good read.
Phoebe Falconer is an Auckland reviewer.