Twenty-five years after Bret Easton Ellis left us with “images so violent and malicious that they seemed to be my only point of reference for a long time afterwards,” in his debut novel, Less than Zero, he’s revisiting Los Angeles with a sequel of sorts in Imperial Bedrooms. Zero’s narrator, Clay, has returned to LA, but this time he has a score to settle: “They had made a movie about us,” he says in the first line, “based on a book written by someone we knew.” Clay, it turns out, wasn’t the narrator of Zero. Instead, an acquaintance turned Clay’s first trip home from college in New England