A decent and happily married man, Derek Cartwright finds himself dreaming of murdering his resident mother-in-law. And when by chance he meets the repellent Hugh Packer, a stranger who is also lumbered with an elderly dependent, what had merely been a midnight fantasy suddenly seems a practical possibility. Like latter-day 'strangers on a train', they could swap murders. That is Packer's idea, anyway: 'You've got a problem, I've got a problem, and together we've come up with the perfect solution. The sooner we get the jobs done the better.' Derek Cartwright knows he can never bring himself to murder anyone not even an old man incapacitated by a stroke. But ea展开