The Antidote continues addressing her unborn son, recounting her time at the Milford Home for Unwed Mothers. She describes the tight-knit community of pregnant inmates—Stencil, Melody, Nathalee, and others—who endure abuse, illness, and shame together. Nathalee, pregnant by her own father, dies in childbirth. The young Antonina Rossi (Toni) finds love among the inmates rather than from the judgmental nurses.

A new arrival appears: Zintkala Nuni, called Marguerite Fox, the Lakota survivor of Wounded Knee who was kidnapped as an infant by General Leonard Colby and raised by suffragist Clara Colby. Toni learns Zintka's true history—her abuse by the General, her escapes from boarding schools, her work in 'Indian Pete' Culbertson's Wild West show as a cowgirl, and her successful journey to Pine Ridge to find her people. Zintka is now pregnant, likely by the General himself.

Through Zintka, Toni recognizes her own complicity as a settler in the dispossession of Native peoples, understanding that her family's homesteading was part of a larger war. Their friendship deepens cautiously, marked by shared trauma and tentative trust.

On Easter, Zintka organizes an escape with Toni, Stencil, and Melody to roller-skate in an abandoned barn. The euphoric outing ends when men capture them and drag them back. In the parlor, Malvina prepares the red leather straitjacket as punishment. Zintka tries to flee and is caught by a deputy.

While the others stand silent, Zintka is forced into the straitjacket and taken to the attic. Toni learns the home's true lesson: 'Better you than me.' Days later, in unseasonable heat, Zintka gives birth to a stillborn boy in the attic. When she returns, she will not speak to Toni, who carries the shame of her silence forever.