A petty thief (Robert Downey Jr.) stumbles into a screen test while on the run from police, and before he knows it, he's in Hollywood preparing for a movie role.
His studio pair him up with a gay private investigator (Val Kilmer) to research his part, but it all gets a bit too literal when he gets embroiled in a murder mystery case - all for the sake of impressing his high-school sweetheart, who is also a struggling actress (Michelle Monaghan).