Three men—Dr. Ken Tashiro, Dr. Jules Masson, and Perry Lawton—are trapped in a bathysphere when a seismic upheaval hurls them beneath the waves. They are rescued by the crew of the supersubmarine Alpha, commanded by Captain Craig McKenzie. The astonishing reveal is that McKenzie is over 200 years old and that the Alpha, along with Latitude Zero, has roots stretching back to the early 19th century.
Guided by McKenzie, the rescued visitors are taken to a hidden Latitude Zero, a remarkable utopia fifteen miles below the surface where the equator and the International Date Line intersect. Here, people from all over the world who disappeared at sea live ageless lives. The city quietly advances humanity’s technology and culture, shielded from the greed and political strife that plague the surface world. Yet beneath this serene surface, a dangerous clash of ambitions brews: Dr. Malic seeks to seize Latitude Zero’s power, while he uses his influence to bend others to his will.
Malic’s plot intensifies when he abducts Dr. Okada, a Japanese physicist allied with McKenzie, and his daughter Tsuruko Okada. He compels Okada to assist in his schemes and orchestrates grotesque experiments, grafting the wings of a condor to a lion and using the brutal punishment of transplanting a brain into a fearsome creature known as the Black Shark’s commander, Kuroiga. The stakes escalate as Okada’s rescue becomes imperative, and McKenzie mobilizes a rescue party that includes Dr. Anne Barton and others to confront Malic on his island base, Blood Rock.
The interdiction culminates in a high-stakes infiltration. The team, equipped with James Bond–style devices and rendered resistant to harm by a special bath, penetrates Blood Rock, fights through defenses, and reaches the control center to liberate the Okadas. As they attempt their escape, Malic boards the Black Shark and fires a devastating onboard laser at the intruders. In a decisive turn, Capt. Kroiga abandons Malic and attacks the weapon, but the battle ends in tragedy as the island’s cliffs collapse onto the submarine, destroying the base and killing everyone aboard.
Only Lawton longs to return home. He is rescued by a United States Navy vessel, where he discovers that all memory of Latitude Zero has faded from his mind. Just when he resigns himself to the possibility that the adventure was a dream, the ship receives a cryptic message: a cache of diamonds has been placed in a New York safe deposit box in his name, and the orders shift toward Latitude Zero once again.
