Young girl Chinatsu inherits her grandmother's mission and becomes the forest postman of Aolan Town. Relying on the power of the wind spirits, she undertakes countless undeliverable thoughts of the mortal world: apologies too late to be spoken, cares for distant family members, and endless longing for those who have passed away. She transforms everyone's yearning into letters, borrowing the long wind to cross mountains and seas, allowing regrets to echo. While healing other people's emotional knots, Chinatsu finds herself trapped in the pain of never having said a proper goodbye to her grandmother.