Cybernetic genius Tabor Ulrich creates a perfect mechanical duplicate of Admiral Nelson. His plot: to make the crew of the Seaview think they are fighting World War Three. In doing so, the sub will launch nuclear missiles at the China, Russia and the USA. After the holocaust, Ulrich plans to take over and usher in "the age of the cyborg".

Admiral Nelson is contacted by an agent claiming to be from the Office Of Naval Intelligence. He gives Nelson a cryptic message that the current nominee must not be allowed to become Secretary of Defense, no matter what it takes.