Ian McEwan never fails to write beautifully and hauntingly, whatever the subject matter. That gift is particularly, perhaps perversely, stunning when he writes about horrifying things. However, he writes here about a type of horror, as experienced by one of the main protagonists, that is bewildering and unbelievable in its intensity. In turn, the outcomes and consequences of that horrified reaction do not seem believable, either. For such a slim set piece, I found this a tedious read.