In case you couldn’t follow the murder mystery, take a look at highlight inside the box for this point by point plot layout.
Dexter had hidden his daughter away in the loony bin and replaced her with a look-a-like so that he could get the lawsuit dropped. But the daughter’s European boyfriend was coming to visit, so he had to kill her to bring the ruse to a close (the boyfriend would see through the double). Harmony’s sister came to town to find her father, whom she thought was Dexter. What she found was Dexter having sex with his daughter’s double. Thinking it was incest, she hired Perry to film it (using Harmony’s credit cards) and then killed herself since it seemed like both of her fathers where abusers.
This movie was so much fun. I absolutely loved the constant breaking of the fourth wall and the witty repartee between Val Kilmer and Robert Downey Jr. was spot on.