Luz Avila's mother abandoned her when she was a very young child to be raised by her grandmother, who she calls Abuela. When Luz is a grown woman, Abuela insists on making a trip to her home village, Angangueo, in Mexico, where the monarch butterflies migrate each year, but Luz is reluctant to interrupt her life. Abuela dies before they can make the trip, and Luz, tormented by regrets, decides to make the journey with Abuela's ashes, driving from...