Ever since Spencer Plain's parents disappeared, he's been staying in Bearhaven—a secret city where bears talk, go to school, develop secret technology, and plan missions to rescue others who need help. Spencer's been planning, too. He's in training as an operative with the Bear Guard, so that he's ready to go help rescue his parents. They've been captured by Pam, who runs an illegal ring of rare animal trading and has been training an army of bears under his control. The Plains are being held at the Hidden Rock Zoo, which is Pam's formidable, fortress-like base. Spencer and the team will have to sneak in, find his parents in the maze of the zoo, and make their escape. Or at least that's the plan. But when it starts to go wrong and Spencer and Aldo are cut off from the rest of the team, it will take some fast thinking, some serious stealth, and a lot of teamwork to get everyone out safe!

A few weeks ago, Spencer Plain had never been to Bearhaven. He was rebuilding a computer and eating peanut butter toast and going to school. Normal, human things. But now his parents are missing, he's living with a family of bears and learning how to speak Ragayo (the bears' language), and has already been on a rescue mission that saved two cubs and their mother. Spencer's ready to go on more missions, but when he uncovers a secret that every bear's been keeping from him, he storms out of Bearhaven, determined to find his parents. While he's gone, his best bear cub friend, Kate, is kidnapped, and soon Spencer is caught up in a daring mission to bring her back before it's too late!

It starts with a chase. When Spencer Plain is pulled out of school in the middle of the day, he never expects to be speeding down the highway with his uncle, trying to outpace the car that's tailing them. And he certainly never thought he'd find himself fleeing from a bear through the woods. And when he hears the bear say "We've been expecting you," Spencer knows he's just uncovered a whole world he'd never imagined. He's brought to Bearhaven, a secret oasis his parents created for bears. But there are depths to Bearhaven that Spencer and his new bear cub friend, Kate, start to uncover. Spencer finds out he's been there before, even if he can't remember. He also stumbles into a rescue mission being planned, to save a bear in danger. He knows he can help, and he's desperate to find clues to his parents' whereabouts, so he and Kate decide to take matters into their own hands - even if they discover a secret that could threaten Bearhaven's future!