Young Robby Yates thought he had found a hidden secret maze of tunnels under the Havershire Public Library. But when he is rushed to the hospital with what looks like a bite wound, the employees in charge of the facility panic. Feeling they have no choice but to close the building down, they evacuate and prepare to padlock the doors once again.

Jack Hawkins and the Silver Eagles are among those who are banned from the library. Believing the stories of haunted tunnels might be exaggerated, the team enlists the help of Colonel Moody's marines to execute a daring recon mission into the subterranean levels under the main floor.