Thirteen-year-old Ivy North is an adventurer. She can pitch a tent in four minutes flat, knows the local landscape like the back of her hand, and she's an expert map reader. There's just one problem. She's afraid to go outside. But when her little brother is transformed into a kestrel by a powerful sorcerer, Ivy is the only one who can rescue him. Following him through a mysterious hole in the garden wall, she emerges in Underfell -- an enchanted realm that seems like the Lake District she knows, but is dangerously different. Battling her dread of being out in the open, Ivy must gather...