Forget JF's jolly Nursery Crimes and Thursday Next books.  This one is much darker.  Set in a somewhat parallel world where the UK freezes over for the entirety of winter, requiring the inhabitants to hibernate in special dormatoriums.  A drug can be had to stop the user dreaming, and thus reduce energy expenditure, but it has sinister side effects.  Into this world, a young man with no family takes a job that will keep him awake all winter, can he survive not only the winter but the people who live in it?