"Bernadette Fox is notorious. To her Microsoft-guru husband, she’s a fearlessly opinionated partner; to fellow private-school mothers in Seattle, she’s a disgrace; to design mavens, she’s a revolutionary architect; and to 15-year-old Bee, she is her best friend and, simply, Mom. Then Bernadette vanishes. It all began when Bee aced her report card and claimed her promised reward: a family trip to Antarctica. But Bernadette’s intensifying allergy...