Set in the fictional town of Blue Bay, Wild Things: Diamonds in the Rough opens with the widower and daughter of a wealthy woman fighting for a pair of extravagant diamonds, known as "mother and daughter." Also involved are a local troubled young girl on probation, a vain physician who refers to himself in third person, and a parole officer.

Like the previous Wild Things movies, this one too starts with a meeting in the Blue Bay school auditorium for a speech on sex crimes by a cop and probation officer (Dina Meyer) who has personal experience with rape. In the auditorium we meet the bad rich girl Marie and the innocent Elena with a troubled past who is on probation herself, poverty-stricken and lives in a trailer. The two girls of course don't exactly get along. Marie stands to inherit two giant diamonds from her deceased mother. However she cannot obtain them until she turns 18. Stepdad Jay, in turn, is in deep financial troubles and is not inclined to let the girl get the diamonds. Jay also has an interest in pretty young things and invites Elena over to the party he organizes for Marie. The issue is who will end up with the diamonds and what intrigues they will devise to get them.

This movie, like the other two in the series, maintains a strong lesbian sexuality content theme throughout it.

The plot reveals in the end that both the female leads, Elena and Marie, are in a relationship and have actually plotted against the step father. The movie ends showing that the probation officer is actually the mother of Elena and the step father was actually the biological father of Elena and the rapist of the probation officer.