The movie follows Joe (Dallesandro), a heroin addict, throughout his quest to score more drugs. The episodic plot occurs over a single day and centers around Joe's problematic relationship with his on-off, sexually frustrated girlfriend (Woodlawn). During the course of the day, Joe overdoses in front of an upper-class couple, attempts to fool Welfare into approving his methadone treatment by having Holly fake a pregnancy, and frustrates the women in his life with his drug-induced impotence.