This very short novel is about an encounter between the narrator as a 14 year old and his 23 year old half-sister, each of whom has a reason for hiding in the basement of the appartment block in Rome in which his parents live.
This has many of the wonderful qualities of Ammaniti's other novels (I've the only three I think have been translated - I would recommend them all very strongly): a very sensitive grip on the hopes, aspirations and fears of young people just turning into adults, the creation of episodes that combine deep feeling with comedy, and forward narrative drive - it's a very easy read.
If I prefer Ammaniti's other novels, it's mostly that they are simply more substantial - but also that here I found that the set-up of the main situation took quite a bit of the book (and was not the most interesting/captivating part), that the framing device (of a first and last chapter set 10 years later) seemed a bit obvious, and in 'Black Cat' paperback when you finish reading the novel, you are faced with 20 odd questions for discussion, asking why the author refers to Batesian theories etc - which I could have lived without!
Having said all that, there is very much to enjoy. I look forward to the next novel!