The book opens on the very eve of the Second World War, with five cousins on holiday at the Cornish home of their Aunt Helena and Uncle Richard (all upper middle class). Four of them (two young women, two young men) are aged 19 or 20, the fifth is Sophy who is just ten. There are also the twin sons of the local rector, who has also taken in a Jewish refugee couple, Max and Monika, from Austria. The novel traces the lives principally of these eleven characters during the war, much of it set in London. Under the intensity of life in war-time, the young people lose any conventional inhibitions they might possibly have had under other circumstances. (I say `possibly', because uninhibited behaviour had been the mark of certain young socialites in the 1920s). One can hardly keep track of the sexual permutations and combinations between them. Even middle-aged Uncle Richard and Aunt Helena have unorthodox liaisons. It is all rather rackety, and in the first half of the novel one feels the characters are driven more by sensuality than by anything deeper, with emotions only superficially engaged. But in the end they do become more deeply involved emotionally; some psychological complexities then emerge (especially for Helena and Calypso) and the reader's sympathies slowly become engaged with them. Most of the story is told as a war-time narrative; but at the end of some chapters we move on forty years or so, when those who are then still alive are converging for Max's funeral and look back on those years; so we learn something about what has happened to them since.
Some of the characters come more alive than others in the book. Especially successful, I think, is the portrait of Uncle Richard, for the most part just avoiding caricature. Calypso, the eldest of the cousins, and Sophy, the youngest, have some personality, as do Max and Monika; some other characters are not rounded out at all. All of them talk in short laconic sentences (the greater part of the book consists of dialogue), and only Richard, Max and Monika have a way of speaking which is in any way distinctive.
There is humour in this book and pathos; it shows that the intensity of war-time life brought its pleasures as well as its sorrows. It is a good read, but I think it lacks the subtlety of a great novel.