“This is the sequel to "Mr. Churchill's Secretary" (which I did not read), set in WWII England. Maggie's fiancee a RAF Pilot is MIA, which complicates a possible other relationship (but we find out more about this in the end of the book, which is a lead up to the next in the series).
So Maggie, flunks out of the Phys. Ed. portion of spy (MI-5) school and is sent back to England. Maggie is then assigned to Windsor Castle to ostensibly teach HRH Elizabeth maths, yet in reality to thwart a possible attempt on the life/kidnapping of HRH Elizabeth, by Nazi sympathizers, in order to restore the throne to Edward & Mrs. Simpson.
In the sub-plot: Maggie is to meet up with her estranged father, also an MI-5, who has the knowledge of the truth behind her mother's death. At a code camp, a decrypt has gone missing and the spy who stole it is found murdered in a London hotel. A Lady in Waiting at Windsor is also murdered...... and HRH Elizabeth is kidnapped......
I liked most of the story/plot, although Maggie allowed one of her obvious suspects to go unresearched.... I'm not overly fond of the upcoming installment, because it seems too "contrived" (I'm not going to add a spoiler).
I would recommend this book/series, it seems to be (in my opinion) lighter fare than Maisie Dobbs.”