One New Revelation Can Change Everything. This is, ultimately, a tale of exactly what the title says. As a dual timeline tale, the linkage here is rare, but rare in the sense of the now-mythical banana chocolate chip cookie from Chips Ahoy - done once years ago, and *may* (HOPEFULLY, in the case of the cookie, I've missed it ever since!) eventually come back.
Discussing the 2010s era timeline at all is a spoiler in that it isn't mentioned at all in the description of the book (at least as it exists at publication in August 2024), but it was one that I could very much relate to given my own family's history. It was also the timeline where this book could be classified as a romance, but that is all that I will say here.
The WWII story is compelling, though we've actually seen its pivotal moment in at least The Last Day In Paris (Book 1 of this series), if not The Paris Orphans (Book 0). The story here is more both how we got to that particular moment and what happens after - both compelling, if at least slightly different, mysteries.
Overall this was a tense book full of both the peril of WWII in so many facets as well as the long tail of its aftermath in so many different ways. Very much recommended.