Before the dialogue even starts in director Aaron Posner's frothy production of "The Two Gentlemen of Verona," three of Washington's top actresses -- Lucy Newman-Williams, Kate Eastwood Norris and Holly Twyford -- strut to the lip of the stage as baggy-pants clowns and serve up the usual preshow instructions to the audience with some laughable pantomime. Posner is tipping you off that it will be their night: None of these women has a leading role, but among them they take on every supporting part, playing nobility, a dog and everything in between.

Oh, and beyond that actorly razzle-dazzle there's a rather serious love story to tell. Note the single red rose spotlighted on the railing of the balcony over the Folger Theatre's stage and the sensuous way the knockout blonde with bedroom eyes inhales its aroma and then slowly glides its ripe bud down her lovely neck. . . .

In other words, we'll have our vaudeville and our romance, too. It's a sensible approach; "Two Gentlemen" is a largely knockabout comedy with a current of betrayal so dark it almost can't plausibly be resolved. (The play's controversial sudden ending screams for directorial modernizing.) Posner strikes a tone that's half-dusky, half-devil-may-care, much like the jazzy yet heavy-lidded love songs -- "Fever," "My Funny Valentine" and more -- that dominate Kevin Hill's sound design.

The story hinges on a rude breach of friendship as Proteus, sent by his father without much warning to the court of Milan, decides to make a calculated play for Sylvia, his best friend's girl. This is despite the fact that he has an appealing girl back home -- Julia, played as an adorable nut-job by Karen Peakes.

As Proteus, Ian Merrill Peakes (Karen's real-life husband) is reasonably sweet in his early scenes, then shows glimmers of Richard III once his character sets his sights on Sylvia (Heidi Armbruster, who looks like a real mid-1950s dish in the satin gowns and tight angora sweaters provided by costume designer Kate Turner-Walker). Posner turns up the dramatic heat during Proteus's bad-boy soliloquy, sandwiching the character between the two women while Brian Hamman's slow but likable Valentine -- the friend that the changeable Proteus is shafting -- gazes on.

Such lurid noir tricks, while effective, are fleeting, especially with Twyford, Norris and Newman-Williams jetting on and off, making generally rich work out of what can seem like slim pickings in lesser hands. Twyford and Norris sprint around the stage as the foolish but bright servants Speed and Launce; one runs up a staircase while the other slides down a fire pole as they giddily seek each other out. Norris's Launce is not only dim but glum -- the tiny bowler and high-waisted trousers she wears are the perfect complements for her simpleton shtick -- and she provides excellent setups for Twyford as Crab, Launce's cheerless dog (a role usually played by a real dog but which Twyford turns into a sad-eyed delight here).

Newman-Williams, the most bluntly efficient of the bunch, puts persuasive macho gravel in her voice as the Duke, Sylvia's father. It's one of several roles played in masks, and despite what appears to be guidance toward broad simplicity by mask and movement director Patty Gallagher, these characters are the least animated, in part because the actors' voices are slightly muffled (their mouths aren't quite left in the clear by mask designer Aaron Cromie). The rampant doubling goes a whisker too far when Newman-Williams, Norris and Twyford, wearing two masks apiece, play six outlaws where Shakespeare called for only three, and for an instant the acting becomes a festival of neck-whipping head turns that keep you strictly focused on the stunt.

Otherwise, Posner keeps the show admirably balanced. Daniel Conway's set, with its subtle art deco curves and round white lanterns floating like champagne bubbles high above the stage, looks like a ballroom in waiting, ready for dancers to begin whirling at a moment's notice. The entire cast effortlessly shifts from dark to bright as needed: Hamman's Valentine manages to be wonderfully slow-witted next to Twyford's deceptively astute Speed (who sports Harold Lloyd's round glasses and some of Harpo Marx's antic maneuvers), Armbruster's lovely Sylvia reveals a spine of steel as she rebuffs the increasingly repellent Proteus, and Karen Peakes delivers a gem of a comic soliloquy over a love letter that Julia impetuously rips to pieces.

As for Newman-Williams, Norris and Twyford, their protean effort saturating the background and amusingly coloring in the margins is ultimately irresistible. Strictly speaking, they're not the centerpieces this time around, but as the groovy Motown curtain call makes clear, they're pips.

The Two Gentlemen of Verona, by William Shakespeare. Directed by Aaron Posner. Lighting, Dan Covey. Approximately 2 hours 15 minutes. Through Dec. 19 at the Folger Shakespeare Library, 201 East Capitol St. SE. Call 202-544-7077 or visit www.folger.edu.

Holly Twyford, putting on the dog with Kate Eastwood Norris, and at left with Brian Hamman in "The Two Gentlemen of Verona" at the Folger Theatre.