The play's the thing in "Criminal," but in this twisty little caper movie it's not about a piece of theater but how to play the con, the grift, or as Richard Gaddis puts it, "the frame." Gaddis, played by John C. Reilly, is a Los Angeles con man who ekes out a living bilking the odd C-note out of old ladies and well-meaning strangers. When he takes a young Chicano man named Rodrigo (Diego Luna) under his corrupted wing, the two embark on a day-long tutorial in two-bit bunko schemes. (The plot thickens when Gaddis introduces Rodrigo to his sister, played by Maggie Gyllenhaal.)

It's not entirely clear why Gaddis has suddenly chosen the scruffy kid to be his protege -- he insists that his usual assistant, "the Jew," is somewhere out there, ready to come back -- but in time, when one of Gaddis's cronies turns up with a multi-thousand-dollar scam that's too good to pass up, a con within a con is definitely afoot; it's just difficult to tell where one ends and the other begins.

"Criminal," by first-time writer-director Gregory Jacobs, was produced by George Clooney and Steven Soderbergh, and it possesses the same light touch the latter brought to the remake of "Ocean's Eleven." This movie itself is a remake of the critically acclaimed 2000 Argentinian film "Nine Queens," and it breaks the oft-unheeded rule about remaking perfectly good movies. Ultimately, once the coup de grace has been delivered, the director's light touch simply becomes lightweight: For all the tells and shills and marks and psychological loop-de-loops, "Criminal" doesn't come near the taut machinations of, say, David Mamet at his most diabolically complex.

Still, Jacobs -- who for many years was Soderbergh's assistant director -- keeps things moving at a sprightly pace, and cinematographer Chris Menges does a terrific job of capturing L.A. in all its mercurial glory, from the city's seedy downtown to the airbrushed perfection of Beverly Hills' manicured boulevards. (Most of "Criminal" was filmed on location in the rococo lobby of the Millennium Biltmore Hotel, which becomes almost a character in itself throughout the film.)

At its core, "Criminal" is a sort of subversive commentary on acting, as Gaddis explains to Rodrigo the finer points of winning people's trust. Rodrigo's success has less to do with skill or amorality, Gaddis explains at one point, than the fact that he looks "like a nice guy." Reilly, with his choirboy's mug, might as well be talking about himself and the beguilingly angelic Luna. They are both terrific to watch, even when the viewer can see "Criminal's" big reversal coming down Main Street (the fact that it arrives at a different corner than expected doesn't add much zing). The main reason to see "Criminal" isn't for the mental workout it might offer but simply to watch these two appealing performers act and act and act.

Criminal (87 minutes, at the Avalon, Landmark E Street and Muvico Egyptian) is rated R for profanity.

John C. Reilly, left, and Diego Luna get their act -- and acting -- together in "Criminal."