The Secret Zoo is a middle grade mystery fantasy novel written by Bryan Chick and published in 2007. It is the first book of a six-book series chronicling the adventures of Megan, Noah, Ella, and Richie as they uncover the secrets of their local zoo and the threats these secrets pose to their world. The book is light-hearted in tone but explores deeper themes including the importance of caring for nature, the power of family, and courage.

This guide refers to the 2007 Second Wish Press paperback edition. Citations refer to page numbers in this edition.

Plot Summary

Megan Nowicki ventures to Fort Scout—the treehouse she and her friends, “the Adventure Scouts” hang out in—where she believes she left her glasses. While there, she notices shadows moving along the rooftops; four monkeys have escaped from the Clarksville City Zoo and are roaming the streets. Noah does not see the monkeys or believe her when she tries to tell him about the incident. Months later, Megan goes missing from the Clarksville Zoo. Noah, Ella, and Richie—Megan’s brother and two friends—are the only ones who continue to look for her after the town gives up. They receive an unexpected clue when a bird flies into their treehouse and gives them a poster telling them to visit the Mr. Tall Tail exhibit.

Mr. Tall Tail, one of the zoo’s monkeys, gives Noah a page from Megan’s diary detailing her adventure investigating the zoo’s mysteries. Each page leads him and his friends to another exhibit until they have two pages of the diary. A red-haired security guard called Charlie Red chases the Adventure Scouts around as they go from display to display. When he catches them in the Chamber of Lights, they ask too many questions, and he calls for backup to drag them out. The backup guard, Tank, tells Noah to be at his mailbox at home at midnight for answers.

The answers come from a cheetah who brings a third page from Megan’s diary and a magic key that will open every zoo lock. Instead of waiting for his friends, Noah rushes to the zoo to rescue her. When he arrives, he uses the key to get in and goes to the penguin exhibit, where Podgy the Penguin takes him through a secret tunnel into the Inside—the way insiders refer to the Secret Zoo when “outside.” Noah, Podgy, and Blizzard, the Polar Bear, spend a night in an igloo before Blizzard carries them across the arctic tundra, passes through a curtain, and enters the City of Species: the heart of the Secret Zoo.

Meanwhile, Ella sees Noah rush to the zoo, and she wakes Richie so they can follow. They climb over the wall and land in the rhino enclosure, where Little Big Horn carries them out of his pen and to the central zoo. Prairie dogs excitedly guide the two through their tunnels under the zoo and into a different sector of the Secret Zoo. They all cross the pasture and find a curtain into the City of Species, where they reunite with Noah.

In the City of Species, Charlie Red finds them again and chases them into the Forest of Flight sector; the group narrowly escapes with the birds’ help, including the supposedly extinct dodo bird. On the forest floor, a man called Mr. Darby rescues the Adventure Scouts from Charlie Red. Mr. Darby seems to be in charge and answers some of their questions, including where they believe Megan is. He convinces the Scouts to help him and then proposes the idea to the Secret Society, an organization dedicated to helping endangered animals, which begrudgingly agrees to the rescue mission. 

Mr. Darby, Tank, the Adventure Scouts, and their animal friends go through a newly reopened curtain into the Dark Lands, where the sasquatches—creatures who are half animal and half human—live. The Dark Lands is where Mr. Darby believes Megan landed when she crossed into the Secret Zoo. Teams go in different directions, looking for Megan while avoiding sasquatches; Noah and his team come across a herd of sasquatches. They fight, and it is close, but the Adventure Scouts win. Mr. Darby tells everyone to fall back to the city. Everyone does except Noah, who refuses to leave without Megan. Podgy accompanies him and learns to fly so he can carry Noah up a cliff to a cave with a red Adventure Scouts emergency flag hanging outside it.

Inside the cave, Noah finds Megan and a sasquatch; Podgy aids their escape, and they, along with their friends, make it back to the City of Species unharmed. Mr. Darby offers the Adventure Scouts membership in the Secret Society as Crossers—members who regularly travel between the Secret Zoo and the real world. They choose to postpone their decision for another day. They leave and return home, reuniting Megan with her parents while the Shadow Master—a man who lives in shadows and wants to acquire the secrets of the Secret Zoo—watches them from his shadows, waiting for the opportune moment to strike.