Harvey's Last Night on the Avenue concerns a sensitive young man who joins a group of his friends on a bar crawl the night before he moves from New York back to his hometown in Texas. An obsessive and socially awkward person, Harvey ruminates over many of his minor social faux pas that he perceives as huge errors. As the night goes on, he accrues more and more faults in his mind, and becomes increasingly unable to connect with the people around him.

When the groom's oldest friend, Cole, finds out his best friend, Jason, is getting married, he escapes from the institution he has been incarcerated in and makes a surprise visit to serve as the best man. Something does not seem right between bride, Gretchen, and groom. None of their friends seem to fully support the marriage and have secrets of their own. Unresolved about their relationship and endlessly obsessed with the groom, Cole stirs up everyone and everything, making it a weekend to remember.