William McGraw

A range war threatens to erupt when the daughter of a cattle baron falls in love with the son of her father's archrival.

A Smithsonian Institute professor employs Mike Nelson to salvage a German submarine sunk off the coast of South America. But two 'hard-hat' divers in conventional diving helmets and lead boots are after the same prize.

A pretty magazine photographer employs Mike Nelson to help her film a sunken barge off the coast of Mexico. Despite Mike's warnings, she gets trapped at the bottom of the sea.

Mike accepts the challenge of Blaze Green, an expert female swimmer, to race underwater from the California coast to Catalina Island. Blaze -- hungry for the publicity she'll get if she beats Mike -- pits trickery against Mike's superior underwater skill.

Joe Ross, featured performer in a water ski show, drowns during the underwater finale to the new act. Mike investigatesand learns an unidentified SCUBA diver was spotted near the death scene. Mike meets the killer in a fierce underwater struggle.