This book is based on a true story, the story of Emmett Till who was murdered for whistling at a white woman.
Hiram Hillburn is a Mississippi native, but his family doesn't really share the cultural assumptions of the south. Hillburn tells through narration about his life, his love for family and food, and his father's decision to move to Arizona. There, Hiram saw his life in Mississippi in retrospect. He explains that it was in Arizona that he realized how thoroughly racism shaped his experience of Mississippi.
He returns to Mississippi to hang out with his grandpa through the summer, and he meets Emmett Till in a river where Till was drowning. Till goes fishing with R.C. Rydell, an old friend, but he notices almost at once that his demeanor has darkened. When they talk, R.C. says horrible racist things. He attacks Emmett Till. Before long, Till turns up, dead, and two white men are asked to stand trial for the killing.
Hiram finds himself subpoenaed, unable to leave because his testimony is important for the trial. Hiram's grandfather and step-grandmother, Naomi, urge him to consider his own safety. If he stands up for Emmett Till, perhaps he'll be next. Hiram considers his options, thinking about his grandfather's advice. He slowly starts to piece together that perhaps the grandfather knows more than he's letting on. It turns out, Grampa helped to lynch Emmett Till himself.
Hiram is never actually allowed to testify and the two murderers are acquitted. Still, he confronts his grandfather for his racial prejudice, his racism, and his willingness to commit murder. The grandfather is stone cold. He admits his involvement, but is not remorseful whatsoever. Hiram leaves back to Arizona and reconnects with his own father, understanding that his dad was probably the victim of abuse, since Grampa is violent and hateful.