Purgatory reveals recent DNA and other forensic evidence (unavailable at the time of the murders), as well as other troubling developments, including allegations of juror misconduct, that suggest the trio did not receive a fair trial. The film includes new interviews with Echols, Baldwin and Misskelley, who are now in their 30s, and many of the subjects of the first two documentaries, including John Mark Byers and Terry Hobbs, stepfathers of two of the victims and frequent targets of the media (and each other).