At the end of the 1950s, in a more innocent America, a brutal, meaningless slaying of a Midwestern family horrifies the nation. While in prison, Dick Hickock, 28, hears a cellmate's story about $10,000 in cash kept in a home safe by a prosperous farmer. When he's paroled, Dick persuades ex-con Perry Smith, 31, to join him in going after the stash.

On a November night in 1959, Dick and Perry break into the Holcomb, Kansas, farm house of Herbert Clutter and family. Enraged at finding no safe, they wake the four sleeping Clutters and brutally kill them all. The bodies are found by friends who come by before Sunday church. The murders shock the small Great Plains town, where doors are routinely left unlocked. Detective Alvin Dewey of the Kansas Bureau of Investigation heads the case, but there are no clues, no apparent motive and no suspects.