No matter, Rowena is on to her next ambush.
She gets a tip that a celebrity businessman (Bruce Willis) is a serial seducer of female employees, a story that gets juicier when one of his alleged victims turns up missing.
Rowena poses as a temp at his office to get a closer look at Willis' character, who does not disappoint - he's every bit the smarmy, leering, con artist his reputation promised.
She pretends to be seduced by this rich and powerful guy, discovers she likes it a little.
The whole thing has the stale odor of a Joe Eszterhas-Paul Verhoeven mess from the 1990s, when a panicked Hollywood began to chase after the porn industry's billions with soft-core sleaze.
When's the last time Hollywood made a good, sexy thriller?
"Perfect Stranger" is made briefly interesting via its use of online intrigue - Rowena entraps her boss by entering his favorite cheaters' chatroom, but can she be sure it's him on the other end?
Her techie intermediary (Ribisi) has a big crush on her, and is in a position to impersonate Willis' character.
There's a good thriller to be made one day about the way the Internet both reveals and disguises its users, but this isn't it.
Ultimately, the movie isn't much interested in the Internet angle. It has what it imagines to be a much bigger agenda, preparing us for the sort of boffo surprise that seems to have afflicted so many thrillers in the post-"Sixth Sense" era.
Movies have gotten better at constructing narratives that contain and conceal these mega-twists, but less adept at infusing them with characters who will make audiences care about the implications of the Big Reveal.
The best of the recent lot is "The Prestige," a movie that likens a movie to a magic trick, with a three-act structure that mimics the three stages of the classical magician's art (the pledge, the turn, the prestige).
The trick, though, is the easy part. As "Perfect Stranger," and "Premonition" show, it's the magic that's hard to come by. *
Produced by Elaine Goldsmith Thomas, directed by James Foley, written by Todd Komarnicki, music by Antonio Pinto, distributed by Columbia Pictures.