Richard Kuklinski sits for a series of prison interviews that make up this HBO documentary, describing decades of contract murders committed while he lived as a husband and father in suburban New Jersey. He walks through his methods calmly, including his signature use of cyanide and frozen storage of bodies that earned him the nickname the Iceman, and recounts a childhood of severe abuse that he says taught him early to inflict pain rather than feel it. The interviews are unadorned: a camera, a table, and a man who shows no visible remorse while describing killings he estimates in the hundreds. Family members and law enforcement voices appear only briefly around the edges; the film's weight rests almost entirely on Kuklinski's own account and the gap between his flat delivery and the horror of what he's describing. It offers no reenactments and little outside context, just a killer explaining himself in his own words, and lets the discomfort of that sit unresolved.