On October 12th, 1978, Nancy Spungen, girlfriend to Sex Pistols bassist Sid Vicious, was found dead at the Chelsea Hotel in New York. Sid was quickly accused of murder. Six months later he died of a heroin overdose and the case was closed. Per Sid's mother's request, Alan G. Parker set out on a journey to discover who killed Nancy. Through conducting 182 interviews, re-examining NYPD evidence, and gathering a thorough understanding of the zeitgeist of those times, Parker delivers a moving film.