"The Heat of the Day" follows the complex interactions of a small group of characters in wartime London, none of who is unambiguously who they claim to be. Surrounded by the unique rules and sensations of a country at war, they both rely on each other and threaten each other, using ominous and largely-unspoken powers and secrets to make life difficult for everyone around them.
On the surface it has the plot of a thriller (an intelligence agent is blackmailing a woman because he knows her boyfriend is a traitor), but that's only the first layer and it's the least important. The second layer is the constant uncertainty of who is who, why they say what they say, and what sort of ominous secrets do they hold, not to mention the influences that war and secrets and uncertainty have on people's behaviour.
Unfortunately even THAT layer of plot is subordinate to the novel's real, central focus: the extremely complicated mental and emotional interplay between the characters whenever they gather in different combinations. I say that's "unfortunate" because the bulk of the novel is dense, head-to-head dialog that veers into psychology and philosophy for dozens of pages at a stretch. People come together, they debate, and they debate some more. They talk about their own thoughts and impressions in such an artificial way that it's like witnessing a therapy session for neurotic poet-philosophers:
"Anything one must say, one must say as soon as one can. One cannot time feeling--at least, as you know, I can't: I suppose that's where to women most men seem to blunder. No, you must face it: all along the line I'm not half so clever as you seem to have thought--or half-thought?"And on and on and on.
People don't talk like that. It's not even artificial in a "deeper level of language" sort of way. It's not the kind of language that resonates, it's the sort of thing you'd read in the rough notes for a textbook. Everybody in "The Heat of the Day" both talks and thinks that way...and most of the novel is them talking and thinking, alone or in pairs, in a succession of increasingly dreary rooms.
But there's something else underneath it all which manages to hold it together: the mood. A sense of approaching danger and a deep, wicked, selfish wartime hopelessness. Most fascinating is Louie, a character so tangential to the plot that she need not even be there...but her petty, stupid uselessness is what informs the rest of the book and puts everything else in context. It all begins and ends with her, even though she has no actual influence ON anything.
That tells you something important about "The Heat of the Day," but I'm not sure exactly what. I found the book befuddling; though I'm impressed by Elizabeth Bowen's writing, and though I found the more tangible and restrained sections of the book to be beautiful and slightly terrifying, the book itself was an annoyance.
I've gotten my hands on a complete collection of her stories and I look forward to reading it: my impression of Bowen is that her obsessive and searching eye is much better suited to short stories.