An 80-year-old widow grows close to a homeless young man who spends his last $12 buying her birthday flowers. Months after her death, her family invites him to the reading of her will. But when he opens a mysterious wooden box, her son panics. What was she hiding? The first time my mother invited a stranger to Sunday dinner, my brother Peter asked whether she'd lost her mind. I told him to lower his voice. Mom was standing at the stove, humming a song Dad used to sing, and I hadn't heard her hum in years. My name is Grace. I'm 52 and a mother of two grown children. Until that spring, I thought I understood my family pretty well. Peter and I had grown up in the same small house, with a father who repaired anything that broke and a mother who never let anyone leave her table hungry. Dad died eight years ago. Afterward, Mom kept busy with her garden and church friends, but her evenings were lonely. She never said so, but I could tell by how long she kept me...