Until the Last Leaf Falls. The Turning Year

To keep memories, he had to become part of the story. Niles has built a life of quiet routines: a library no one visits, a glade of trees tucked away in a courtyard, and a profound loneliness. Messages begin to appear-written on autumn leaves by a stranger who seems to know him better than he knows himself. They introduce Niles to a world where trees hold memories and a man who, like Niles, hides his loneliness behind his purpose.
For the first time, Niles feels seen, but his mysterious guide is bound to the turning of the seasons. As the last leaf falls, he disappears. And Niles discovers that the only way to bring him back is to build something even rarer than magic: a community. A quiet, tender magical realism romance about two lonely people learning to connect. The magic is subtle, the longing is real, and the ending will stay with you.