Though Abu Osama, a seasoned Al Nusra fighter in northern Syria, has eight sons, he prays for each of his two wives to have twin boys: four more soldiers for his cause. Talal Derki’s shocking, harrowing documentary follows Abu — a sniper and expert in defusing mines — and his son Osama, a charismatic 12-year-old being trained as a jihadi. Director Derki, posing as an Al Qaeda-affiliated filmmaker, spent two years getting to know the family; his camera provides a nonjudgmental but unflinching immersion into the world of radical Islam, intensified by the unfolding tragedies of a heartless civil war. Osama, a sensitive boy prone to fits of rage, is initially terrified when sent to a brutal military camp. But soon, Abu hopes, his son will be ready to fight. (JS)