"The Sapphire Child " - pre World War two Northern India (now Pakistan)

Two young friends, a British boy and an Anglo-Indian girl grow up in what is now Pakistan but was then British India. Their parents run two hotels inhabited by some long term guests. His father is still haunted by his experiences during WW1. 

Then WW2 starts.

A good story and a good inside look in that part of history. It is a Part 2 of a series but you can read it as a stand-alone novel. (I was not that keen on Part 1 but you might like to start there anyway).