After a violent storm at sea, the inert body of a man is found on the beach near the Naval Undersea...

Mark investigates the disappearance of three scuba divers, two of whom are 'replaced' by waterbourne...

When a space capsule crashes in the ocean near the Cetacean, Mark and Elizabeth agree to investigate...

Elizabeth is kidnapped, one of dozens of scientists held prisoner on the island of Felicitos, contro...

Schubert threatens to cause worldwide flooding by using powerful microwaves to melt Earth's polar ic...

When a multimillion-dollar underwater probe malfunctions and begins attacking any ship that travels...

Mark, investigating a power outage, discovers a centuries-old hawk statue from the legendary civiliz...

The oceans are leaking through a fissure in the ocean floor. A con-man named Muldoon agrees to guide...

Using his genetic scientists, Schubert produces a giant jellyfish which he intends to release unless...

Mark is somehow linked with a man named Billy, existing in a wild west town, who appears to be his t...

Schubert attempts to make a satellite weapon to knock out Earth's communications. However, to power...

An underwater landslide transports Mark to Verona, Italy...in the days of Romeo and Juliet.

C. W. develops a Jekyll-and-Hyde personality after swallowing a mysterious liquid.

Mark re-encounters Muldoon, his nemesis from "Giant," who is using a sea monster to make island nati...

An impish little man enters an underwater station and causes the crew to become irrational simply by...

While investigating the mysterious loss of three ships in one part of the ocean, Mark and the crew o...

Mark goes undercover to investigate members of a carnival planning to break into a museum. The only...