As long as she has plenty to read, nine-year-old Olivia Brown doesn't mind spending the summer at Aunt Lila's rural home. An hour into the drive from Arlington, though, she's already tired of hearing complaints from her brother Aiden, who's 11 and easily bored. She's also concerned about getting along with her twelve-year-old cousin Virginia Temple and her brother Jacob, age 10, who will be joining them from Florida.Shortly after their arrival at the old house on the Rappahannock River, Aunt Lila gives Olivia a key that will lead the four cousins to adventure, making their visit to Hull Crossing and the nearby Northern Neck much more interesting.