VEILED BEHIND the romantic antics of a group of bored upper-middle-class sorts at "Heartbreak House" is an intellectual circus, with some of George Bernard Shaw's most memorable characters giving voice to his convoluted cerebral clowning.

Source Theater has mounted a careful and very funny revival of Shaw's busy play, a metaphor for troubled WWI England, which also accommodates asides on the economics of romance, and how science and the world are marching hand in hand toward annihilation.

Shaw's eccentric characters are walking, talking (mostly talking) Ideas, representing love, pride, commerce and empire, among other things. Director John MacDonald sets the whole dotty bunch to dashing farcically in and out of the many doors of this Chekhovian country house, spewing Shaw's densely packed lines at a feverish rate. As usual, the sweet surfaces of Shaw's women soon give way to shrewd wit, and Source's female performers rise smartly to their roles, particularly Deirdre Donohue as delightful Hesione Hushabye, endowed with mischievous seductive power and a flair for the well-placed giggle. Laura Giannarelli is fine as Hesione's sister, prim, arrogant Lady Utterword; as is Lynn Steinmetz as naive Ellie Dunn, who becomes disillusioned with love, money and, finally, the world in the play's three acts.

As ancient, crazy Captain Shotover, Dick Harrington overdoes the doddering at first, but recovers his character admirably for the conclusion. Reese Stevens is an endearing, gangly Mazzini Dunn, and William Hamlin is appropriately dashing as chameleonic Hector Hushabye.

But as the "bloated capitalist" Boss Mangan, blustery John Lesko confuses passion with volume, and Bill Largess grossly overplays his cameo as the burglar.

Matthew Cooper has provided one of Source's tidiest, most attractive sets, and this lively production manages the neat feat of making the three-plus hours of Shaw's talkfest disappear pleasurably.

HEARTBREAK HOUSE -- At Source Theater Main Stage through February 1.