Mike Keene

While chasing a coral poacher who deafened Flipper, Ranger Porter Ricks is knocked out by an underwater explosion. His rescue depends on his sons at home, who are completely unaware of the danger as they care for the injured dolphin.

Wyatt's feud with the Clanton Gang continues.

Flint goes in search of a young woman who was taken by Indians as a child.

While studying the activities of whales, Mike Nelson observes three men entering a strange chamber deep in the ocean. When only two of the men emerge, Mike investigates and learns the remaining man is a famous missile expert held prisoner by enemy agents. Mike changes places with the scientist in an attempt to outwit his captors.

Mike Nelson interrupts an underwater survey in the Gulf of Mexico to save a diver whose air line is snarled on jagged rocks. This rescue plunges Mike into life-or-death clashes with man and underwater beast.

Two prospectors find a radioactive fish in Florida. Convinced that the fish will lead them to a rich underwater uranium deposit, they employ Mike Nelson to track it with a Geiger counter. Mike's daring and quick action prevent the prospectors' greed from resulting in disaster.