For River, understanding her community-and how she fits in-will take some investigating. River Wren has always lived with her family on the shores of Lake Saturday in the Backwoods of Sourland Mountain in New Jersey. It's 1978, and River's life seems simple and predictable-at least on the outside. Her best friends and neighbors are George Janson and Joe Farrington. Their dads are best friends too-they even form a heavy metal band called Beowulf's Brother. But on the inside, River is struggling against strong currents. Her father's parents, who died long before she was born, were from the nearby Lenni-Lenape tribe. River wants to learn more about her ancestors-especially since she and her dad look different from the people in their neighborhood. But River's dad refuses to talk about his past, no matter how many times River asks. Meanwhile, her sister, Savannah, keeps sneaking off into the woods, and River worries she's up to no good. And then there's George's mother, who has been acting strangely, quickly swaying from happiness to anger in a way that frightens River. When River, George, and Joe decide to start the Three Detectives Club, River begins investigating the mysteries around her. Can she keep her sister out of trouble, find a way to help George's mom, and get her father to open up about their shared heritage? The third book in the Sourland Mountain series, Country of the Birch Trees follows a kind, persistent thirteen-year-old as she deals with crucial questions of identity, family, and community.