Wholesomeness is the main virtue of this update of the iconic youth mystery novels, which transports the title sleuth to present-day Los Angeles, but not the only one. Director Andrew Fleming squeezes in enough wit here and there to keep adult eyes from glazing over, including a tart – but never snarky – acknowledgement of the formula conventions in which he’s engaged (there is a strange caretaker introduced as a “strange caretaker”). Above all there is the plucky Emma Roberts, whose Nancy has the sort of innocent smile Paris Hilton likely lacked at birth. “I like old-fashioned things,” Nancy matter-of-factly explains to her bewildered, fashion-obsessed new classmates. As benign as a home-baked brownie, Nancy Drew counts as one of those artifacts.