
The book recounts two murders in the small town of Ada, Oklahoma. Both victims are young women. In both cases, the local and state police investigating the case are stumped. But with a toxic blend of extremely circumstantial "evidence", shocking crime scene photos, junk science, inexpert experts, jailhouse snitches and critical "dream confessions" induced by near-torture tactics, the police pin the murders on four young men of the area, two per murder.
The "innocent man" of the title is 30-something ne'er-do-well Ron Williamson, a schoolboy baseball star whose dreams of playing in Yankee Stadium dissolve in the low minors in a mix of arm injuries, booze and the onset of mental illness. By the time of the murder that consumes most of Grisham's tale, Williamson has washed up back home in Ada, and deservedly earned a reputation as a loudmouth loose cannon of sorts. Still his worst crime is passing a $300 phony check.