Chapter 4 begins with the story of Lt. Colonel Monterrosa’s arrival in Perquín, where he rounds up and presses into service ten villagers as guides. He then splits the Atlacatl Battalion into five units to begin “Operation Rescue’s ‘hammer and anvil,’” with the several units that were advancing north from the Río Torola being “the hammer of the operation, [and] […] meant to push all the guerrillas in the zone toward the anvil of the Atlacatl and crush them against the best troops the Army had to offer” (47). However, the guides pressed into service didn’t know this at the time, instead thinking they’d be killed, as often happened in towns where allegiances were fluid, with towns being occupied by guerrillas, then the army, then back again.

The chapter then shifts focus to the Atlacatl Battalion and Monterrosa, providing more history and context, as well as to the state of the Salvadoran Army in general and the US’s role therein. Monterrosa’s troops stood apart from the rest of the Army for several reasons; for one, they had been trained by American Special Forces. Danner asserts that “[m]ostly, though, [the difference] came from Monterrosa,” who was “aggressive, charismatic,” and “a soldier of the classic type” (38).