Global Inspector Burt Campbell and Dr. Ai Eto are making a frantic escape back to Earth aboard a crippled clipper after destroying the moon base. The Master has escaped to whereabouts unknown and taken Penelope with It. The Earth is in the midst of an apocalyptic destruction, and the dogs are trapped on the island of Hawaii. Campbell must save them, but when he arrives the island's volcanoes are already erupting and the dogs are missing. Campbell and the injured Eto become trapped on the erupting island. In a desperate search to escape before the island destroys itself, they encounter Lady Baldwin, a pirate who has vowed to kill Campbell. The threesome escapes immediate death aboard an antiquated and flightless clipper which leaves them vulnerable to tsunamis and attack from other pirates. After battling their way to New Atlantis, the secret underwater city containing a portion of Earth's survivors, President Cathcart takes Campbell into her confidence. Her primary concern is saving mankind before the Master can dominate the planet. Yet Campbell is only worried about finding Penelope and avoiding Dr. Dupree, a scientist desperate to learn Penelope's secrets at any cost. Campbell also discovers a potentially great evil growing in the perceived tranquility of New Atlantis. It's an evil that could replace or destroy mankind. Abruptly, Penelope shows up at New Atlantis. She's under orders from the Master to return to Mexico City with Campbell or It will destroy New Atlantis. In a final confrontation with the Master, Campbell meets his ultimate destiny.