It's told by schoolboy Ade, who does the shopping and chores for his agoraphobic mum, who just wants to sleep all day in their high-rise flat in south London. We follow Ade's struggles at school, his friends and enemies. It's all very well observed by Ho-Yen, a former teacher.
And then there's something else - a local building collapses, then another... and then more, sometimes with people inside. Bit by bit, the recognisable, identifiable world of school and shops is taken over by a crisis right out of John Wyndham. By midway, Ade is trapped in his high rise, which is itself under threat, and the rest of the book is taken up with his efforts to survive in the scary new normal that is now.
The prose style is straight forward but full of telling detail and strong emotion, with Ade having to navigate the traumatised but persevering grown-ups. There are some terrifying, vivid scenes such as when Ade ventures out beyond the safety of the block. I also liked the more subtle stuff: Ade sometimes doesn't quite understand what he has witnessed but we do - such as when, towards the end, we learn the cause of his mum's condition.
Really, what makes this so compelling is not the nightmare world conjured but the effort of people to look out for one another in the midst of awful crisis. The sort of book to linger in your thoughts and dreams long afterward, haunting a whole generation.