In Frederick Lonsdale’s 1923 drawing-room comedy, married aristocratic idlers Willie and Margot must navigate the complications of having both been caught in flagrante delicto. Lonsdale’s writing is sophisticated, and director Jessica Thebus has assembled a talented cast for this Remy Bumppo Theatre Company revival. But the first act, comprised mostly of plot setup and character exposition, is so well behaved you’d think the actors were playing for their great-grandparents, and overly earnest American acting further weighs down dialogue that should be thrown away. The second act, however, is brisk, witty, and disarmingly moving, thanks in large part to Linda Gillum’s spritely, mercurial turn as Margot. With a finish so engaging, it’s not difficult to forgive the extended false start. Through 1/8: Wed-Sat 7:30 PM, Sun 2:30 PM, Victory Gardens Theater, second-floor main stage, 2257 N. Lincoln, 773-871-3000, $27.50-$38.50.