Bruce Willis (as I remember) is a private detective/investigator and has the mission to find the girl that had been exchanging letters with a XXL ex-prisoner (Robert Maillet?). The investigator then ends meeting a scientist that works on a Hadron Collider thingy and he has a wife, which the big guy thinks is the girl that had been mailing him. The investigator falls in love with her and her brother was actually a crossdresser that was mailing the big guy. In the end of the movie, the Collider explodes and the investigator drives away from the explosion with the scientist's wife.
Sorry about my bad english!