The novel is written in the form of a letter by a young Vietnamese American nicknamed Little Dog, whose life mirrors that of Ocean Vuong. The letter is written to Little Dog's mother Hong, more often called or translated as Rose (hồng). The novel has a nonlinear narrative structure.
The novel also recounts the life of Little Dog's grandmother, Lan, who escapes an arranged marriage during the Vietnam War and becomes a prostitute. She marries a white American soldier and gives birth to a child, although the father of the child is most likely another man. The child is Little Dog's mother, Rose. She is barely literate, having left school at the age of five when her schoolhouse in Vietnam collapsed during an American napalm raid. She suffers from posttraumatic stress disorder as a result. Rose marries an abusive man but eventually separates from him.
Working in a nail salon, she struggles as a single parent living in Hartford, Connecticut with her son and her mother Lan. Living in America as refugees, the three can barely speak English. Little Dog, who is gay, is abused by his mother throughout his childhood. Halfway through the novel, Little Dog meets a young white man named Trevor while working on a tobacco farm one summer, and the two begin a romantic relationship. Trevor eventually becomes addicted to opioids and later overdoses and dies.