Peculiar packages

"Ella has moved to the spooky town of Windy Hollow to live with her Great Aunt Raven. She is kept busy by a series of odd jobs arranged by her mysterious aunt. Postmaster Silverton asks for Ella's help delivering packages. She is surprised to see an abandoned house on her route. But when she returns the following morning the package she dropped off yesterday is gone and in its place is a cryptic note for the next order"--Amazon.