If you could be more specific it would be helpful. How near the end of the story? Are you just looking for a summary? Tom, a young boy, is sent away to spend the summer at the rented flat, or apartment, of his aunt and uncle. He is lonely and homesick but late one night discovers a mysterious, enclosed garden that although invisible during the day, appears after midnight. His excursions into this garden take him into a magical world where the past and present intersect, and he finds that he can visit with a girl from the past, who becomes his friend. For Tom the summer passes in days, but it seems to pass in years for the little girl, who gradually grows up and matures with each visit.