Lin Wan is a college student who works at a secondhand bookstore. One day, while sorting through old books, she finds a letter from ten years ago. It is full of affection, but has no signature or date. Intrigued, Lin Wan decides to find its owner. During her search, she meets Gu Yan, a young man who is just as curious about the letter. Together, they set out to find the person who wrote it. As they dig deeper, they discover that the letter is intricately connected to their own past...
