This is a multi-layered story within a story, so a little like the film “Synecdoche, New York” by Charlie Kaufman.
It is set during the rehearsal of a rather weak play about a fictitious meeting between WH Auden and Benjamin Britten near the end of their lives. So the actors play actors playing other people, and they argue with the writer and stage manager about how to perform it, fiddle with props and fluff their lines etc. That makes it sound pretentious and obscure, but it's clever, funny and thought-provoking.
The play they are performing echoes “The Tempest” and hence a poem that Auden wrote about it. In the period covered, Brittan was writing an opera based on Thomas Mann’s “Death in Venice”, which, with is pederastic undertones, has uncomfortable parallels with his own life. Because he is struggling with it, he is considering reviving his earlier collaboration with Auden. Humphrey Carpenter (who once interviewed Auden and was eventually biographer of both) is also a character in it.
Because of its structure, its plot has a less obvious trajectory than his other works; in some ways it is a miscellany of musings, loosely held together in concentric contexts. But somehow Bennett makes it work.
My favourite line is, "Style is the sum of one's imperfections" (words Alan Bennett ascribes to WH Auden). I think that means I can claim to be stylish, whist remaining modest.