Describe China Iron's life before she leaves on her journey with Liz.

China Iron lives with La Negra and El Negro, a Black couple, when she is a small child; no one knows where she came from. She is neglected and abused by them, and ultimately given in marriage to Martín Fierro when she is still a child, in order to settle a gambling debt. She lives in poverty with the abusive Martín and bears him two children, all before she is 14 years old.