"I can't shake the feeling that you're just blowing through town with a carnival." Dialogue from Watching the Detectives, a romantic comedy with shadings of L.A. noir that played at Tribeca this year. If the film were made sixty years ago, the male lead would first be seen in a downmarket private investigator's store front, leaning back in a chair with his feet up on a desk, as the dangeous female comes waltzing into his life. Today, it's a downmarket indie video store, where Neil (Cillian Murphy) lounges with his fellow employees, savoring their status as increasingly rare birds in a neighborhood being invaded by behemoth video store giants. Into the store one day waltzes Violet (Lucy Liu) a first-time customer who continually asks Neil questions about this and that and when he answers, points out that she's talking not to him, but to whoever is on the other end of her invisible Bluetooth handless. She eventually sidles up to the counter and announces that she has no membership and no driver's license, but she wants to check out anyway.

What follows is a gentle spoof on femme fatales and the men they inevitably drag along by the ear. The plot can't handle any seriously evil or crooked intentions on the part of Violet, so instead she's portrayed as having a screw loose -- a woman who enjoys walking her men into elaborate practical jokes and then doubling over with laughter every time they fall for it. She begins by showing up at the restaurant they choose for their first date falling-down drunk. When Neil refuses her aggressive, drunken come-ons, she reveals the put on and tosses it off as a half-joke, half-test to see if he would take advantage of her. In the real world, the man would run for the hills of course, but it somehow works here. For his part, Neil is a classic noir stooge who understands intellectually that he's being taken for a ride by this woman but can't help himself. "I've lived in Tasmania, Cape Town ..." Violet tells him. "That sounds incredibly ..." "Exciting?" "I was gonna say made up."

The film's best scene is one that you can see coming a mile away, involving Violet, Neil and a couple of Neil's friends in a park. I won't give it away, except to say there's a picnic basket and a pretty funny joke involved, all the more funny because you completely expect it. "I have a condition called boreaphobia," Violet says at one point, which is supposed to excuse all of her behavior, and as with most noir babes, it does because the sex appeal overrides normal decision-making. The stooge will put up with pretty much anything as long as the bait is still being held out in front of him. As first-timer Paul Soter (of the Broken Lizard gang) said when I spoke to him recently, the dangerous and unpredictable woman is a pretty common male fantasy. Still, it's not one with a long shelf-life -- the eccentric female will typically become less and less tolerable, which is a tough fact to square with the romantic comedy element of this film -- romcoms demand a happy ending, right?

So where do you take it? The longer Watching the Detectives goes on, the more aware you become of watching 'performances' instead of characters with normal human instincts that would have them running for the hills. This is especially true of one late scene, in which Violet goes way too far and sets up an elaborate staged kidnapping, all because she apparently has nothing better to do with her time except to put her boyfriend under great stress. Neil's response is more or less what you'd hope for, but still, how did it even get to the point? Luckily, the scripting and directing of the film is sharp and clever enough so that it rarely strays off a path that's enjoyable, even when it's diving into areas that are completely fantastical. Soter's best decisions, however, were reserved for the casting: Murphy and Liu are never anything less than watchable, and they bring enough energy and concentration to their roles to keep the whole juggling act going longer than most other actors would, I imagine -- fans of them and fans of noir should get a kick out of this film.