I am surprised by the low ratings here, since this is a magnificent, dark little thriller imo. On second thought, I can see how Lasdun's style is not for all tastes - but it certainly is for mine. As in The Horned Man, he gives us a realistic, introspective psychological thriller that is written in nuanced, articulate prose, one that focuses on a possibly disturbed, 30-something male protagonist. In an interview once, Lasdun identified himself as a fan of Patricia Highsmith, and one can clearly see that there is a connection between them. I would bet a healthy sum that she would have appreciated his work as much as he appreciates hers.
This tale begins fairly peacefully, as what looks to be a languid summer is getting underway. We are introduced to a pair of cousins, Matthew and Charlie. The former is a struggling cook, the son of a man who embezzled a large some of money and then vanished; the latter is a well-off financier, somewhat cold and abrupt, but seemingly a responsible and decent guy overall, who is generous with his less successful cousin. For some reason, Matthew repeatedly refers to Charlie as his friend as well as his cousin, which I found disconcerting, but anyway . . . We spend all of this book inside the head of Matthew, and even though he is welcome to stay in Charlie's spacious vacation home in fictional Aurelia, New York, and to spend time with Charlie and his wife Chloe, he still is an outsider in their comfortable existence, and tries to win their favor by running errands and cooking nice meals for them.
The troubles begin to appear slowly, but steadily. For one thing, Matthew and Chloe have an unspoken, never-to-be-expressed attraction to each other, and that is one of the things that begins to eat away at our troubled protagonist. Lasdun is superb at carefully and eloquently unwinding a dark, nasty scenario. It begins to become apparent that Chloe is up to something with another man, a masculine filmmaker named Wade Grolier - although it is not entirely clear what. Matthew almost confides his suspicions to his cousin a number of times, but fear and a sense of propriety hold him back. Instead, he decides to do some solitary snooping and investigating, a decision that eventually has catastrophic consequences.
By the end of the story, Matthew's troubled tendencies are increasingly on display, and Lasdun milks the tension between the characters perfectly. The choice of title is a fascinating one. By using this well-worn phrase (which makes it seem like the kind of book one might pick up in a train station), the author gets us wondering which of the main characters it will apply to - and the reader does not find out until the last paragraph.
Don't trust those 2 star reviews. This is an excellent literary mystery, with a slowly developing but effective plot, and some depth to the characters (particularly Matthew and Chloe). I listened to an audio version of it, in which Charles Constant gives a very good reading.