It's January 2020, and Miriam is already getting a sense that the world might be ending. First, she learns that her best friend, Esther, has died. Then her faith in God --- in everything, really --- follows suit. Her job teaching Scripture at a private Christian school suddenly seems untenable, so she quits. Thankfully, the postal service is hiring. While Miriam finds comfort in her route, the mail truck can hardly outpace the memory of her lost friend and eroded faith. She finds herself composing letters to Esther that she will never deliver, reflecting on their shared childhoods and deep understanding of each other's difficult families.