PJ's unit in Syria attacks the ISIS-held city of Al-Shaddadi, but heavy combat evades them once again. A frustrated PJ heads home to the States, leaving Levi and the others behind. Feeling stuck in Tennessee, Jeremiah seeks to do the opposite; he misses war and is desperate to return. As new faces join Pete's medical team in preparation for the impending siege of Mosul in Iraq, all the volunteers do their best to walk the paths they've chosen--which soon proves fatal for one.

PJ returns to Syria, inspired by Levi's sacrifice and intent on reaching ISIS' "capital," Raqqa. In Iraq, ISIS is losing ground in Mosul but stages a diversionary attack in the city of Kirkuk, where Italian volunteer Alex leads his men into battle against them. Meanwhile, Pete reaches a breaking point as casualties stack up in Mosul.