The Case of the Secret Passage

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, lead them farther and farther into the passageways where Amy Jo and Becky uncover a fiendish plot. Before they can warn the police, the girls are caught in a trap where there seems no possible way of escape. Astride, Ginger and Oreo, Amy Jo and Becky find the courage and ingenuity to bring the criminals to justice.