First of all, the film has Bill Nighy in it. We are fans in our household, so he's enough for us. The drama has a strong cast overall, led by Romola Garai's passionate performance, but all helping to illustrate the emotionally (and politically) contrasting time for the youthful main characters just before WWII in England. The camera work is lush and gently moves the suspenseful story along through a rich English landscape and into grand vacant interiors. It's been twenty years since I've been in that landscape, and I found myself wanting to strap on some Wellies and walk through the screen right into it. While a nostalgic depiction of the setting, the film treats wartime corruption with scrutiny and critique.
The story surrounds a female lead who's personal discovery takes a dark turn into a conspiracy theory of the English upper class's conspiring efforts with Hitler to buy a version of peace for themselves. Ultimately the film could have been smarter, I imagine with the cast, and faster like modern thrillers as critics have said rather than the slower, naive old-school unfolding that it is. In the end though, I think it is well done and the departure from common patriotic nostalgia into the shushed decomposition of wartime is worth exploring.