Queenie only sees Maddie three times throughout the year, including the meeting at Manchester when Queenie's brother Jamie was in awful shape (several fingers and toes lost, got bombed in the air) and when Queenie practiced her parachute jumps.

Then, in September, Queenie also sees Maddie as her ferry pilot, in which Queenie successfully completed a mission in France (which was an impressive moment), which we informed about slightly later. The two meet as Maddie was recruited a few months earlier as to fly special missions!

Then, in early October Queenie and everyone else involved in Operation Dogstar gather at the SOE airfield, where they find out that one of the operatives is missing due to an injury (a pilot I believe?). This is a horrible setback as they have been waiting ages for the perfect conditions of this operation - and so Maddie volunteers (and gets the job, much to Jamie's disgruntlement). On October 11th, Maddie flies Queenie to France but are hit by sudden bombs. Queenie parachutes out of their injured plane as Maddie needs to risk landing (which she couldn't do several times) and tells Maddie to "Kiss me Hardy" as her final words. After all this, all the background context is given and the pieces begin to fit.

During this, Georiga Penn interviews Julie for "propaganda purposes" when in reality, Penn is there to check on the condition of Julie. They're able to pass on information after Georgia reveals herself by using Julie's code name, Verity.

And now, back to the main topic, Julie is being transported along with several other prisoners when the Damask circuit ambushes the vehicle. When the rescue attempt goes wrong, Maddie starts to sob - something Julie immediately recognizes (and it's quite bittersweet, with Julie's face lighting up and becoming beautiful once more). She cries out for Maddie to shoot her (saying, "Kiss me, Hardy") and Maddie obliges, killing her friend before the Nazis could further torture and use her.

They bombed the building later on - LET'S FREAKING GO!!

• Maddie - after bombing the Nazi base - is sent back.

• She is interviewed and grilled about what happened during her time in France, in which we can see changes in her personality, how she is now much more volatile and upset over the mentions of Julie.

• She is not court-martialed and is allowed to continue flying, marveling at the fact.

• She receives a letter from Julie mom, Esme, who invites her over to their house, viewing Maddie as one of their own and telling Maddie that she believed that what Maddie did was right (as Maddie told Jamie about her shooting Julie).

I, too, believe she was in the right. Julie would've been sent away to be tortured and experimented on in a concentration camp. The Ending, like the entire book, was dreadfully bittersweet as Maddie will never be the same again, a part of her broken self stuck in France forever.