The Secret Passage

More about the book

While housesitting at the Funderburg home, Amy Jo and Becky discover a hidden door leading to a series of underground tunnels. Strange markings on the tunnel wall, visible only with a black light, guide them deeper into the passageways, where the Pony investigators uncover a fiendish plot. Before they can escape the tunnel to warn the police, the girls find themselves caught in a trap with seemingly no way out.