Trendy jokiness and mawkish sentimentality blend uncertainly in this very slight Christmas grab-bag: overlapping vignettes, all set in and around a New York City department store in the last few days before the holiday. Store-owner Louis Fontaine wanders from department to department, muttering ""Buy, buy, buy."" A vicious security guard hangs around every night, determined to nab the store's ""ghost""--a figure in a silver jogging suit who's been glimpsed here and there, who hides in the store at night. Divorced coffee-machine demonstrator Winifred, whose son is away for Christmas, slowly develops a courtship with equally lonely toy-department manager Muhlstock--who dreams of firing darts at passing children. Most farcically, there's store-window designer Dann Sardos--who's driving himself (and everyone else) crazy by refusing to reveal his big window display until it's esthetically perfect. (He experiments with a headless reindeer, with unnatural acts between Pinocchio and a skunk, etc.) And, most stickily, there are two dreadfully clichÃ‰d figures of pathos: the Santa Claus who's really a skid-row bum beneath his beard, who is transformed by his exposure to the innocent tots (""Hang on, my little friend, hang on to the secret of the stars, and all your made-up games""); and the by-now-obligatory bag lady, who fancies herself ""Queen of the Moon"" and dreams of a long-lost family. Finally, then, the security officer does capture the silver-suited jogger--an orphan boy--and Fontaine plans to use the lad as a publicity gimmick: ""Orphan of the Year. . . . Some sort of tax write-off . . . in the name of compassion."" But, with help from some of the other characters, who now converge in the last few pages, the boy is hugged by the bum-Santa (""His embrace had a meaning the boy could feel"") and escapes . . . while everyone drinks champagne together: ""perhaps the earth itself hung by this fine thread, woven between strangers."" Despite his recent authorship of the E.T. paperback novelization, however, Kotzwinkle (Dr. Rat, Fata Morgana) is a highly unconvincing dispenser of sweetness and light. And only the occasional nasty/funny bits of dialogue ring true in this limp, near-plotless Christmas mini-pageant.