Henry Biedinger

When the State of Florida is plagued with a series of underwater crimes Mike Nelson is called to organize and train an underwater police force. Learning that a thief has just looted a cabin cruiser and escaped underwater, Mike gives his pupils a "practical" lesson. Mike uses his vast knowledge of the sea to trap the thief.

Mike Nelson accepts a job to supervise a diamond diving expedition in South America, but soon rebels when he learns his employers are poaching on somebody else's property. Mike discovers his life is in jeopardy, and uses his knowledge of sharks to capture his would-be murderers.