The Best Man reveals the more intimate side of life for a group of successful college friends who are reunited at the wedding of one of their buddies. With vows about to be exchanged, the groom's best man Harper (Diggs), a commitment-phobic writer, worries that his friend (Chestnut) will find out that he once had an affair with his soon-to-be wife (Monica Calhoun). Harper has good reason to be nervous-he's written about the affair in a steamy new novel just about to hit the stands-and one of the bridesmaids, an ambitious TV reporter (Long), has obtained an advance copy. By the end of the weekend, everyone will have re-evaluated their relationships with each other, with their lovers and with themselves, for better or for worse.