Das amerikanische Atom-U-Boot "Wayne" ist in geheimer Mission unterwegs. Im Südpazifik soll eine neue Raketen-Abschusstechnik erprobt werden. Weder Commander Kettenring (Leonard Nimoy) noch seine Crew ahnen, dass sich feindliche Agenten an Bord des U-Bootes befinden. Die wollen das Projekt sabotieren und die "Wayne" versenken...

The U.S. submarine Anthony Wayne is underway for a top-secret mission. Onboard is a highly classified device that will give the Americans a decided nuclear advantage. The entire mission and the secret technology are threatened when the sub commander discovers his crew has been infiltrated by enemy agents. The commander is charged with trying to protect the device while ferreting out the enemy agents. Compounding matters is the state of the commander's physical and mental condition, which is being questioned by his crew.