It starts with a mistake; most stories do. Ex-model Luz and her ex-military boyfriend, Ray, are squatting in a dusty mansion in what used to be Laurel Canyon but is now, after a California drought of apocalyptic proportions, only “some ruined heaven.” Luz has been famous since birth as Baby Dunn, “conservation’s golden child,” the innocent whose age measures the number of years gone by without swimming pools and avocados. She’s busy trying on the clothes the mansion’s owner left behind when a prairie dog surprises her on the stairs and, unthinking, she kicks the rodent into the library.…