God and Country — Michael J. Scott

Abandoned in Detroit, Peter Baird finds himself in a city no longer recognizably American. Armed thugs roam the streets while the citizens suffer beneath an evil caliph who has taken over and rules the city according to Shariah law.

He is soon captured by the caliph's forces and is given a choice: convert or die. Horrified by the murderous oppression of women and religious minorities, Peter engineers his escape and begins a resistance movement.

Can Peter convince the citizens of this besieged city to reclaim their rightful inheritance? Or will the leaders of the new religion hold greater sway?