A boy. A girl. And one sweet September.

After 10 life-changing years, Jung Soojung is back to the small town where she grew up. Now an aspiting writer, she decides to stay until the end of the month, just enough to hopefully heal her writer's block. There, her path once again crosses with Kim Jongin - the childhood friend she clearly remembers, but now seems to have changed a lot. Then there's the house she used to live with her family, now old, dusty and needs a lot of cleaning. 

This story follows Soojung's 30-day journey as she revisits her past and redefines her future.