John Wayne Gacy has a troubled childhood of abuse. In puberty, Gacy comes to the realizes his attraction to other males. Acting upon his dark desires, Gacy works for a funeral home in Las Vegas. After moving to Springfield, Gacy marries.
John Wayne Gacy's career of crime begins in Waterloo, Iowa. After being sent to Anamosa Reformatory on a sodomy charge, Gacy refines his con artist techniques. When released early, Gacy buys a house with a crawlspace.
While beginning his contracting business and performing as a clown, Gacy perfects his killing techniques using handcuffs and a rope. As one of his victims turns the tables on Gacy, the Chicago police follow up on complaints about Gacy.
Gacy releases two victims who go to the police. As his killing spree continues, Gacy picks up a teenager in Des Plaines. Believing that Gacy was involved in the teens disappearance, Des Plaines P.D. places Gacy on 24 hour surveillance.
While Gacy confesses, investigators begin excavating his crawlspace and identifying the remains of the young boys murdered by Gacy. A map of his crawlspace, his "cemetery", is drawn by Gacy for investigators searching for remains.
Investigators finish the excavation of Gacy's crawlspace and discover there are more bodies on his property. Gacy's trial begins amid rampant homophobia. Bill Kunkle describes his epic closing argument to the jury.
Becoming the first true serial killer celebrity, Gacy writes back to people sending him letters and also begins painting and selling his offensive art. Brian Dennehy discusses his role in "To Catch a Killer". Gacy's execution date is set.
The identification of Gacy's unknown victims is detailed. Theories in the Gacy case are presented as myths are debunked. Gacy's killer clown persona has influenced pop culture through movies and ephemera.