Handwritten Postmark Set

She is the owner of a second-hand bookstore. She found a collection of handwritten love letters on the bookshelf, signed "Xiao Chen", and each letter had only one word: "Ann". She had been curious all her life, and before she died, she handed the book to her granddaughter: "Help me find Xiao Chen." The granddaughter found the nursing home based on the postmark. An old man with white hair took the book and said in a trembling voice: "I have been writing 'Ann' all my life, just to ask if she is okay. If she couldn't receive it, I wrote to the book." The granddaughter asked him who she was, and the old man took out a photo from under the pillow, and it read on the back: Wife, separated in 1966. That book became the only photo of them together in this life.