David Duchovney is a writer. He is writing a book about serial killers. He decides to take a road trip with his photographer girlfriend and visit some "murder sites" to better understand the mind of a serial killer. Brad Pitt is a seial killer who answers an ad from David to share the expenses on a road trip and takes his waitress girlfriend along on the trip. As you can guess, there are many adventures, and murders along the way.
This is a story of self discovery for Duchovny who, with the help of Pitt, gets into bar fights and shoots guns and generally discovers his manhood. Worth a watch, if just for the wonderfully psychotic performance by Pitt