Sam Gribley is terribly unhappy living in New York City with his family, so he runs away to the Catskill Mountains to live in the woods—all by himself. With only a penknife, a ball of cord, forty dollars, and some flint and steel, he intends to survive on his own. Sam learns about courage, danger, and independence during his year in the wilderness, a year that changes his life forever.

Two years ago, Sam ran away from New York City to live in the Catskill Mountains. Now his younger sister Alice has joined him and is quietly living in a tree house of her own nearby. Their peaceful life is shattered when a conservation officer confiscates Sam’s falcon, Frightful, and Alice suddenly vanishes. Sam leaves his home to search for Alice, hoping to find Frightful, too. But the trail to the far side of the mountain may lead Sam into great danger.

Sam Gribley has been told that it is illegal to harbor an endangered bird, so when his beloved falcon, Frightful, comes home, he has to let her go. But Frightful doesn’t know how to live alone in the wild. She can’t feed herself, mate, brood chicks, or migrate. Frightful struggles to survive and learns to enjoy her new freedom. But she feels a bond with Sam that can never be broken, and more than anything else, she wants to return to him.