The years after 1492 in Spain were not good years for anyone but the Catholic hierarchy. Forced conversion and expulsion of Jews, followed by the same treatment for Muslims. 'Forced conversion' is a euphemism: it means vile torture plus the threat (often carried out) of being burned alive. As Ali makes clear, a prime motivation for those persecutions was the church's desire to seize the land and wealth of Spanish Jews and Muslims.
This novel is set in 1499 in a small village near Granada and traces the increasing threats and persecution experienced by the Muslims in the area, starting with a mass book burning the previous year.
My biggest surprise about this book is that Ali chose to focus on a wealthy (formerly) ruling class family rather than on working or peasant class people. It's a bit hard to feel sympathy for those who themselves profited from the conquest of Spain - though I suppose there's a sort of statute of limitations on such things and the Muslims had been in Spain for 600 years by the time of the reconquest.
In any event, Ali paints a picture of a mostly tolerant, well-educated, and urbane Muslim upper class, faced with stinking, brutal, avaricious, and immoral Christian prelates and government officials. You can accept that picture, or not, but he manages to tell a pretty compelling story about a period and place that is mostly glossed over in public school history classes.