The last night in London / Karen White.

Enhanced descriptions from Syndetics:

New York Times bestselling author Karen White weaves a captivating story of friendship, love, and betrayal that moves between war-torn London during the Blitz and the present day.

London, 1939. Beautiful and ambitious Eva Harlow and her American best friend, Precious Dubose, are trying to make their way as fashion models. When Eva falls in love with Graham St. John, an aristocrat and Royal Air Force pilot, she can't believe her luck--she's getting everything she ever wanted. Then the Blitz devastates her world, and Eva finds herself slipping into a web of intrigue, spies, and secrets. As Eva struggles to protect her friendship with Precious and everything she holds dear, all it takes is one unwary moment to change their lives forever...

London, 2019 . American journalist Maddie Warner, whose life has been marked by the tragic loss of her mother, travels to London to interview Precious about her life in pre-WWII London. Maddie has been careful to close herself off to others, but in Precious she recognizes someone whose grief rivals her own--but unlike Maddie, Precious hasn't allowed it to crush her. Maddie finds herself drawn to both Precious and to Colin, her enigmatic surrogate nephew. As Maddie gets closer to her, she begins to unravel Precious's haunting past--a story of friendship, betrayal, and the unremembered acts of kindness and of love.