Marin, one of Louie’s cousins, is an energetic young woman who has recently emigrated from Puerto Rico. When she isn’t selling Avon makeup, Marin is mostly confined to the home, babysitting her younger family members. As an older girl, she is the first to teach Esperanza about certain aspects of womanhood, from sex and pregnancy to feminine grooming routines. She has a boyfriend back home in Puerto Rico, but she enjoys attracting the attention of other men, from the boys that she and Esperanza pass on the street to older working men that she fantasizes about marrying.

Marin’s extended family has threatened to send her back to Puerto Rico, as she’s “too much trouble.”  This is because Marin enjoys dancing and parties, and she spends late nights out on the town. At one of these parties, Marin meets a handsome young man named Geraldo. Later that night, Geraldo is killed in a hit-and-run, and Marin, being the last person to see him alive, is responsible for identifying him and giving a witness statement to the police.

Through Marin’s experience with handling the aftermath of Geraldo’s death, The House on Mango Street subtly introduces the violence and tragedy that permeate poor and underserved immigrant communities, and how it affects everyone, whether they’re the victims of that violence or someone who must bear witness to it. Geraldo’s story, like many of the vignettes, also comments on how lonely and isolating the immigrant experience can be: “His name was Geraldo. His home was in another country. The ones he left behind are far away.” Marin is practically a stranger to him, but she’s the only person who can identify him. Although she can’t articulate why, Marin feels that she has a moral responsibility to manage the particulars of Geraldo’s passing, enforcing the novel’s overarching theme of the importance of community and caring for one another.