Finally watched this again. I still remember how this was a pretty big deal when it was first released, so much in fact that even my parents wanted to watch it (and they're not really into cinema). I guess Houston's popularity played a big part in the film's success, as the rest is pretty basic and formulaic.
Frank is a personal bodyguard who never stays on the job for too long and doesn't want to deal with celebrities. Still, he is suckered into taking a job for Marron, a famous actress. The two don't really get along at first, but someone is after Marron and Frank is one of the best in his field.
Costner is a pretty bland guy and not fit for the part, Houston on the other hand is pretty much playing herself. There are some famous songs attached to this film and some of the are quite tense, but the runtime is excessive and the direction is very mediocre. Not really worth all the fuss.