O'Brien's platoon arrives in "the villages of My Lai" (115). This may surprise readers who knew of the My Lai Massacre and thought there was one village named My Lai; in fact, My Lai was the name of a collection of small villages. These villages were in the area the US Army called Pinkville, named after "the fact that military maps color it a shimmering shade of elephant pink" (114).

In March of 1968, American soldiers from Company C, 1st Battalion, in the 23rd (Americal) Infantry Division, killed several hundred unarmed civilians in several hamlets in My Lai. Company C, or Charlie Company, had suffered twenty-eight casualties from mines and booby traps in the previous months and while the official purpose for being in the My Lai region was to try to wipe out the Viet Cong's 48th Battalion, in March 1968, Charlie Company appears to have taken personal revenge on My Lai. Women, children, and old men were killed, along with farm animals. Crops and huts were burned, and wells were despoiled.

There was worldwide outrage when the story broke in November 1968, and twenty-six soldiers were court-martialed. However, only one was convicted: Lieutenant William Calley Jr., a platoon leader in C Company.