In Shanghai in 2023, in an old post office facing demolition, young employee Lin Xiaoman discovered a mysterious mailbox that could send letters to the past. When she accidentally rewrites the fate of herself and those around her, she must repair the timeline within 48 hours, but in the process she discovers sixty years of love and regret buried between three generations.
Purpose: 1. Regrets cannot be made up for by tampering with time
2. Old and new cities, memories should not be completely demolished
3. Understand the forbearance and dedication of two generations
4. Accepting loss is the answer to time
5. Letters are silent carriers of emotions