When Spencer Plain's uncle pulls him out of school, and they find themselves being chased by a strange car, Spencer does not know what is going on--but soon he is rescued from the woods by a bear, and taken to Bearhaven, a secret refuge his parents created, filled with bears who can talk, where, desperate to find his parents, he and a bear cub named Kate decide to take matters into their own hands.

Spencer Plain's parents are prisoners of Pam, who runs an illegal ring of rare animal trading, and they are being held at the Hidden Rock Zoo, target of the next rescue mission the bears of Bearhaven are planning--but when the rescue starts to go wrong, and he and Aldo are cut off from the team, it will take some quick thinking and serious stealth to save the mission.