This is a very detailed and gritty portrayal of the major players working in the Valley of the Kings in that decade, notably Howard Carter and Lord Carnarvon from England and the archaeologsits from the Met in New York. There were rumors of some shady activities surrounding the opening of Tut's tomb and these were later borne out by documentary evidence in letters and diaries.
The other significant settings and events are a few chapters detailing the death of Frances who disappeared from Lucy's life for a couple of years while she was secreted away in Saranac Lake, NY, a haven for those suffering from TB. The cold clean air was thought to be restorative and shortly before she dies, she contacts Lucy and asks her to come. People hid the fact that someone had TB since it was contagious and carried social stigma. Lucy was able to reconnect with her friend for her few last weeks.
Then there is the contemporary setting of Lucy's house in London, where she is recalling all these events at the prompting of Mr. Fong, who is making a documentary about the discovery of Tut's tomb. Lucy is now in her 90's. She is still friends with one other woman she met as a girl in Egypt, Rose. Rose's younger brother Peter briefly became Lucy's lover at the beginning of WWII before he he was killed, and their baby died. So there are a lot of ghosts in Lucy's life.
The settings are colorfully portrayed and Beauman has scoured historical documents to make the historical people and events as accurate as possible. However, I find Lucy to be a less than compelling character and the book felt slow at times. Nevertheless, I learned a lot--about the discovery of Tut's tomb and the role of Lake Saranac--and that is always satisfying.
See this somewhat more cogent and pointed review in The Guardian or this one from Kirkus.