One Day Only, American Theater Company. Edward Mast’s writing has enough charm, wit, social consciousness, and unpretentious intelligence to make you root for it to take flight even when it’s sputtering to a halt. Set in Klineburger’s Department Store in Seattle four days before Christmas, One Day Only details the dreams, romances, and sorrows of the store’s employees, who turn on one another amid fears of a corporate takeover and rumors that a saboteur has infiltrated their ranks. Suspicion falls on the janitor–a slumming intellectual–who observes with scientific detachment the farcical interactions of the lovably oddball staff. Among them are a wide-eyed schnook with corporate ambitions, a health nut who designs window displays, a love-starved heroine straight out of a Carole Lombard comedy, a show-tune-crooning cashier, and–in one of Mast’s clever touches–a sly talking mannequin with a sirenlike talent for influencing customer purchases.

Nice performances abound in this world premiere by the American Theater Company, particularly from Martie Sanders as the wisecracking mannequin and Ann Noble Massey as the daffy designer. But Mast’s sometimes uninspired one-liners and somewhat static scenes, which include a good many talky stretches about working-class frustrations in a consumer society, work against director Brian Russell’s screwball approach: loopy walk-on characters meant to give the illusion of department-store mayhem only detract from the play’s flimsy plot and sluggish pace. –Adam Langer